Guys - I have just been to Travis Perkins and spoken to a couple of guys there... They have sold me some special thermalite plugs that look like elongated propellors (like the type you may find on a boat but a longer and thinner... They are 50mm long, and you have to drill a 10mm hole in the wall and hammer them in. Diameter wise they are about 20mm across but apparently as you hammer them in, the 'fins' cut into the thermalite and hold tight? I have got 8 of them and 8 bolts that are 80mm long... Obviously I need to put some spacers inbetween the plug and the wall mount but has anyone else seen these?