You've probably figured this out, but to get the most space to work in you either a) take the wheel off (PITA for changing sidelights), or b) turn the wheel OUT rather than in on the side you want to work... Counter-intuitive, but it works.
Also, don't remove the back in wet / damp conditions - do it in a garage when the car is dry-ish so no water or moisture gets in. Otherwise you'll be out there in a few days with a hair dryer trying to get rid of condensation. If you have never had the backs off you may need to get new backs and do this anyway, as the rubber perishes and hardens over time. Cheap though - only about £25 for the pair.