Starter bolt chassis clearance & engine mounts

The lower bolt housing is very tight to the chassis, best advice was to file it back a little: Propped the engine on a block of wood to give room to work & used the Dremel sanding drum & a hand file:

Resulting position with the engine lowered:

Engine mounts

This allowed me to complete the engine mounts, bolting to the chassis:
4mm pilot holes followed by 8mm for the bolts.

Offside there is a problem - the top right bolt is so tight to the chassis rail I can't get the nut on underneath.. I need to think through some options:
    Re drill the bracket rotated a little clockwise <- This + shaped the nut to fit against the chassis
    -or- Use a spacer tube underneath with a longer bolt
    -or- Run with 3 bolts on the offside

Nearside is fine: