I have an old spanner (in the US sense) left over from another bike that I use. Not sure what they call this sort of wrench in the UK, it has a rounded part that fits around the shock and a single lug at the end to stick in the hole.
I also have used an old worn out acrewdriver that I ground the tip off.

Let's hope there's intelligent life somewhere in space 'cause it's buggar all down here. -- Monte Python