For those with no standard issue toolkit.......
If you have tried to change plugs & failed as your plug spanner is too short or too fat to fit.
Try this.

Take one 18mm AF box spanner. (The one I used is a spark plug spanner from an unidentified bike tool-kit that I had acquired some years ago.)

Add an extension to it. I have used another box spanner which fitted over the end & then tack welded them together.

This one is just long enough to do the job but works ok but another half an inch in length wouldn't go amiss....Fnerr Fnerr....
I suppose that you could do it with just a bar or long bolt, but you will need to be able to turn it. On the version above the 2nd box spanner has the holes which you put a bar though to turn.
Simple & cheap, have you seen the price that Storm tool-kit's go for on e-bay?
If you don't happen to have an 18mm AF box spanner laying around at home try your local bike shop or breakers.
Nowt like a bit of Blue Peter engineering to solve a problem.
OK yes it does look a bit pants TBH but then it's silver.....
