7 mm thin-wall tube spanner or hex socket

[James P]

You will need a 1/2" chuck drill (think of that as a "mini lathe") and a angle head grinder with a flap wheel to do this trick, put the deep socket in the drill chuck and while running both, work the flap wheel along the socket till you bring it down to the desired size that will fit in the recess. I would replace the 7mm bolts with allen headed caps (as they should have in the first place).

[David Herbert]

I am not sure why there is mention of deep sockets above but surely it is possible to grind the outside of a 1/4" drive 7mm socket until it fits. This could easily be done by eye, holding the socket by a long 1/4" drive extension and using either a bench grinder or an angle grinder held still by someone else or even ratchet strap it to a pallet (for example). Just go slow and don't try to take too much off quickly. It doesn't need to look pretty, just work.

David