Nat
good work, i prefer screws with allen heads ,
not unlike these I have seen these on ebay, i believe these are the same dimensions as the seat cover bolts ?
http://www.ebay.co.uk/itm/STAINLESS-FLANGED-BUTTON-HEAD-SOCKET-SCREW-DOME-M6-X-20-/370170918888?pt=UK_DIY_Material_Nails_Fixing_MJ&hash=item562fe7f7e8#ht_1226wt_952
steve