Using a standard 17mm spanner to do this job is really difficult if not near enough impossible on the rear plugs.
Actually I didn't have any problem with a straight spanner when taking the coil packs off the other day to get the cam covers off. But the proper spanner with the offset and extra length does look easier and more useful if the plug caps are very tight.You need the special spanner here
So just nipped out to the garage and knocked this up.
Old 11/16in offset ring spanner attacked with angle grinder/hacksaw/file.
Fits perfectly
Help's if you come from a line of engineers and have a garage full of old/odd size tools perfect for recycling.