Well, I went up there on Sunday and I can actually say that the roller WERE accurate. We ran 3 different cars throughout the session @ different times (without telling the dyno operator) which had all been run on a different dyno and got the same results +/- 1 bhp. We ran factory cars and got approx. factory outputs, ran modified cars and got higher levels.

Only problem really was that the rollers drop the wheels in quite a way and a couple of the cars had problems with subframes or kits hitting when setting up. Wouldn't recommend a -60mm or more lowered car on there.

Can't vouch for their work, but one of the blokes was talking about a Scooby they had in for a gearbox leak which they are doing under warranty (seems genuine enough, you can see the leaking oil seal, so no dodginess there IMO)