I now have a copy of the service manual but there are times when I won't have the time/ability/motivaton to do some things and want a reliable and clued-up local outfit to help. Electrical stuff for instance is beyond my own ability.
Thanks for suggestions. I'm booked in at Challenger in a couple of weeks time. That means I can DIY till then and they can clear up anything I can't do. Will post back to let you know how we get on.
Thought I'd post back here and say that I'm pleased with the work done at Challenger. Nothing major - new middle box, caliper carrier, track rod ends but good friendly service. Sensible with parts too so where possible a refurbed part will do.