The Mégane II Owners' Club

I changed the lower engine mount on my Megane Scenic 1.6 last night to cure a banging sound on acceleration and gear changing. When I removed the bolt holding the mount to the subframe/body I found it was 2mm smaller in diameter than the bush in the mount (the thread was undamaged, so its thinness wasn't due to wear). Torquing it up to the recommended torque (55ft-lb) stopped the free play, but is this the right nut and bolt (actually a set screw, to be precise)? My local Renault dealer tells me that the bolt is no longer available, and breakers throw fasteners straight in the bin. Is it just a 12mm bolt, or is there something special about it?
The engine mount looked original (it had RENAULT stamped on the rubber) and my mate at work reckoned that Renault themselves had put 'any old thing' in, just to get the car out the door

as well as that mount, did you have a look at the rear gearbox mount ? if its backwards / forwards movement its not likely to be a side mount ?