Fuel Cap

I opted for the Aston Martin type fuel cap and it comes undrilled but had pilot indents on the underside.
Drilled these 4.5 mm to accept 4mm countersunk bolts which then needed countersinking from the top .
This was a challenge in itself  as the countersink (from screw fix) was too wide to get square on to the holes so with a make shift lathe ( drill in the vice and angle grinder !!) made it thinner so it now fits

Drilled out and countersunk

then it was just a simple job to fit the unit to the car but wanted to make sure that the cap was the right way round so ,,, fitted the cap with all the gaskets as clearance s close tightened it down and placed it on the car so it was facing were I wanted it to then mark the holes

placed on the car at the angle I wanted

I then drilled a 5mm hole and tapped it out 6mm to place a grub screw in the back ( as picture above) so it could not move over time .

Marked the holes and drilled out 5mm so I had a bit of error factor and fitted it looks good .

finished cap