Many thanks for you all for helping me (I've decided to go for it after getting hold of the Haynes manual (#4151)).
There are a couple of questions at the bottom, but FYI.
-- In fact my car went for an oil service today (£190) and as well as pads, discs being knacked (service manager said discs that do 50k miles had done a good job - is he right or just BWM dealer/rip-off speak?) the front caliper is 'sticky' and needs replacement. The only good thing about the service was the courtesy car, a Z4 conv 2.0 litre. Fun for a day but wouldn't switch for my 5 series + the Z4 new is, gulp, £24k (or $40k), staggering!!
Had a good on-line look about replacing the caliper seals but generally seals to be a bad idea, so new caliper it is at £50-60 - Haynes manual says it's pretty easy and actually explains how to refurb it, I don't have enough confidence in my DIY skills to attempt a refurb. But for the record has anyone done, found it easy and worked?
-- So, off to GSF tomorrow for my parts and of course a new tool (mandatory); a piston retraction tool.
-- Questions
I did notice that GSF have stacks of varieties of discs (vented, solid, brands) - Does anyone know the OE make of the DISCS?
When changing the caliper, I have to clip the hose to stop brake oil leaking, when I reconnect do I have to bleed the air out?
Thanks again
Matt