I agree Nitron would be a good choice but make sure you order the right unit. See here for Carlo's experience:
http://www.ukmonster.co.uk/monster/s...ad.php?t=55536
You could check with Boris as to exactly what model he fitted.
Depending on budget and how soon you need it fixed, maybe Cobra's offer of his old Sachs unit might be your best bet. Nitron shocks are made to order and would probably take 4-5 weeks at this time of year. You could fit the snazzy unit over winter and maybe resell the Sachs unit at the same time.