'08 GT gearbox noise.

Hopefully someone out there can help me on this. I have a 2008 GT with manual transmission, when I sit at 30 mph there seems to be a groaning noise, when I take my foot off the gas the noise goes likewise when I put my foot back on the gas it goes, it only happens like I said sat steady at 30 mph. I've also noticed something rubbing on the metal plate between engine and gearbox near the flywheel. I've had to put two washers in between to stop this happening. This is not ideal I know but I'm very limited to who I can take the car to here in England. Any advice would be greatly appreciated.