Dave
Watch out for drum distortion. I purchased a pair of these (also from John Macdonald) many moons ago for my +8. Within a year they had warped quite noticeably and I would was getting a very strong modulation through the brake pedal.
I changed to the different design (suggested by John Mac) offered by Techniques Morgan:
http://www.techniques.uk.com/images/rp_brake%20drums.jpg I have had no problems since.
