Passing trade has dried up, drivers aren't combining local errands with trips to other destinations, and some less physically-able customers can't get to the local shops they used to visit, a survey of businesses in the area revealed.

At the convenience shops that bookend Sunnyhill Road, takings are down by as much as a fifth.

In the Red Lion store, near the Valley Road junction, Sasi says he's seen a drop of 10-20%. "You can feel it," especially during the daytime, he says. "It's definitely made a difference."

"When they opened the school street [around Sunnyhill Primary, at the start and end of the school day] it hit, and now this one," he says. "Everything's going up and our trade's going down, it's not the right route."

Some customers from around a couple of corners, on Valley Road or Gleneldon Road, and the other residential streets that they lead to, can no longer stop off in their car, he says. Residents in that area were very much in his catchment area. "On this side you have the petrol station [on Leigham Court Road] but that side is just the common." The nearest shops they can now get to by road are Sainsbury's and other shops on the high street, and so that seems to be where at least some of them are going, he says.

Sasi also loses out on trade in drinks and chocolate and grocery bits-and-pieces, when his next-door neighbour James, at French deli Le Tour de France, is selling less.

James is cautious about putting firm figures on the drop in revenue over the last month, and is wary too, at this stage, about attributing a tougher business climate solely to the LTN. He'll have a better idea in the New Year, he says. But still, "initial indications" are that the decline is in the region of "20 to 30 percent".

The Candy Box convenience shop and newsagent, also on Sunnyhill but just around the corner from the High Road, is facing the same problems. Raj says his takings are down maybe 20% - "two, three, four hundred pounds a day, and these shops are very high rent".

Raj's traditional customers are also from "that side" - Valley Road, Madeira Road, Gleneldon Road - "not the high street side... They used to come here, people from that side, now they're going the other way". The effect may be getting worse, he suggests - some customers ignored the retrictions at first, when they knew the ANPR cameras on the LTN gates weren't working.

Lambeth's deputy council leader Rezina Chowdhury came into his shop earlier this month when visting Streatham Wells to "talk to residents" and film a video for YouTube, he says, and left her card. "Any problems, call me, email them," he says. "But I complained about it before" - before the LTN was put in place - "it didn't change anything." He and James both end the conversation with a shrug and the same words: "What can I do?"

Just down the hill, Andy at the Thomas Clark dry cleaners says his business has seen a "massive, massive difference" in trade over the last few weeks - and he is confident about putting the drop down to the LTN restrictions, since he has another shop in Tooting and can compare revenues.

They are "easily 20% down", he says, while takings at the Tooting shop are running at normal levels. The Streatham shop is "just not competing".

Again, it's the sudden change in geography that is the problem, he says. "People from Valley Road, Crown Point, the other side of the common - they would normally drive and bring a decent amount of dry cleaning. It's just wiped that out."

At the same time, the business is still wrestling with the higher costs, alongside the difficulty of putting prices up by enough to cover them. "Bills are up double and treble," he says. His gas bill "used to be 500 to 700 a month, now it's 1700 a month. Electricity was 250 to 300, now it's 550. And there's only so much you can put up prices on garments". They've already gone up by a total of 25%, he says, in two stages.

And he's had to start charging for pick-up and drop-off services - not least because "I now literally have to put 20-25 minutes on a delivery" because of the routes he has to take, and because of the increase in traffic. He "feels bad", he says, because lots of his delivery customers are elderly, but he also says it's unavoidable given the cost of fuel, and the longer journeys he's now making.

Andy says there's a productivity loss as well. He's trying to do deliveries early, to beat the traffic, but his other shop still gets opened later as a result of the delays, he says. "This is a slow strangulation at the moment."

Sasi talks about the same problem - that everything now takes him longer. He comes to his business from Tulse Hill, and needs to get to and from the cash and carry in Croydon. All those places used to be in a roughly straight line, with the Red Lion in the middle, but the closures at either end of Valley Road now force traffic out sideways from Sunnyhill into the traffic of Streatham High Road.

And in K and J Garages over the road, they're infuriated by the traffic delays. The business has been there 35 years, John says, and it has a loyal customer base - they're booking into next year, and haven't seen any drop-off. But getting themselves to their jobs has become harder, and they have concerns about their customers struggling to get out of Sunnyhill Road at the end of the day, when they typically come to pick their cars up.

"My journey to work was 6 miles, now its 8 miles and an extra half hour. I left at 8.25 this morning, got here at 10.05," John says.

The garage's motorbike man, Dunstan, has the same problem. "For me personally it's a massive inconvenience." A forced detour around the LTN "has put 20 minutes on my journey". It's also another 20 minutes extra whenever he's collecting customers' bikes locally, he says. And "all it's done is push it out to the schools on Leigham Court Road", he adds.

It's perhaps not surprising that your local mechanic isn't a big supporter of an LTN - "The whole thing's become a cash cow," says John, "Their main concern is how they can get a fee out of a driver."

But there is a bit of balance to their views. "I can see that change is needed," says his son, Jonathan. He thinks the design of the scheme is too restrictive though. "I've not heard anyone say anything positive" about the way the Streatham Well LTN is set up, he says. "People can't stop going to work... You should be able to access Valley Road from one end."

A couple of other businesses in the area aren't too bothered, financially at least. At Sunnyhill pizza place Bravi Ragazzi, they say they've noticed no loss of custom, maybe just an increase in queuing cars outside the door - and perhaps some grumpier-than-usual delivery drivers.

And at the Leigham Well pub, landlord Alex says the same - it hasn't affected business since nobody drives there anyway, he points out. I ask him what his customers think about it. His laugh and invitation to ask them make me think that they might not - yet, at least - be big fans.