Had my rear discs and pads replaced yesterday thanks to maindealerdiscount.com. Informed at BMW Huddersfield that the rear drivers side spring snapped.

Replacing both rears today. Told that there is a 2 year warranty on parts as long as they are fitted by an approved garage. MOT also today so hopefully will get them fitted at Halfords autocentre later today.
Decided not to get eibach springs as they are not original and so will have a negative effect on car insurance and more importantly ground clearance! (Paying particular consideration to the NW pothole/speed bumps dilemma) Quoted £109 each for the springs from Halliwell jones, so not too too bad considering they have a 2 year warranty.