Got round to sorting out all my automotive tools into a single toolbox and got some rails for the sockets, it’s nice to know that the 11mm socket is to be found between the 10mm and the 12mm rather than hunting through a collection.
I’ve also got a cut down wine cork installed in the 21mm socket for dealing with the sump plug. The only 21mm socket I could find in York was an impact socket which actually works out perfectly as it is hexagonal so will grip the flats rather than the corners meaning it will be much less likely to round.
The purpose of the cork is to stop the sump plug disappearing into the socket as it will sit on the cork making it much easier to re-fit.
The gearbox sump and filling/level plugs are also 21mm so this is good for them as well.