The way I do it is with a spark plug socket, put a spanner on the flats and a decent hex bit thru the middle. Go back to halfords, and look in their tool section. You'll see a VERY handy 7mm hex tool with a great big handle on it

To refit the new VW 22m nuts (which you should buy since they're use once!!) use a lambda probe/diesel injector socket. This is even easier becasue they have a nice big cutout in the side for your allen key

Edit: Also depending on the make the strut may have a 6mm or 7mm allen hole, I had 1 6mm and 1 7mm on mine
