Don't know if anyone else has suffered this but I have been getting a sharp knocking under my feet when I accelerated in 1st & 2nd gear.

Finally traced via this thread http://www.edition38.com/forums/index.php?showtopic=354600

Turned out to be the rear sub-frame mounting bolts as indicated there - which gives the P/N of the bolt (Bolt N90823501 - The bolt is a audi part) in question and of a spacer that should go between the subframe and the body.

Having got the parts via TPS, when I finally got the car on the jacks last weekend, I found the original bolts to be, if not loose, not at all tight and easily undone with a normal 1/2" socket-set rachet. When I replaced them with the new bolts I used a longer bar (from a 3/4" drive set) and did them up really tight (they are stretch bolts, so should really have been torque/angle tightened, but I did not have the numbers to follow).

OTOH, fitting the spacers looked to be impossible as the rear sub-frame is a slightly different shape to that shown in the above thread, and I could see no way to get the spacers in without a lot of work and some different jacks.

Nevertheless the knocking has now gone - so that was definitely the problem :-)

I think I heard about this on the VWVortex forums regarding MKV Golfs, and it was fixed by a bolt from a B6 Passat. I'm looking to change to an Octy II soon so this information is helpful, thanks.