I am putting in a new washbasin in my cloakroom, which just has two approx
20mm oval holes in the back of the basin. The wall is plasterboard dabbed onto soft concrete blocks of some sort. The basin didn't come with any wall fixings or instructions. It is 450mm wide by about 390mm deep I presume I need some sort of "fisher bolt" for the wall, and some strong washers larger than the 20mm holes ? Will I need plastic washers as well ? What diameter bolt would be suitable, I'm guessing 8mm or 10mm ?Thanks Tony