Morgz,

As I don't know what 'gert' means, i dont know whether to feel or

If you just want to lower and not uprate the shocks, then i'd say about £100ish for the springs and about the same again to fit by a decent garage. If you want the whole suspension bit (Shocks and springs) then £200-£300 for the hardware and £200ish to fit. (Educated guess)
(Mine were on the car when i bought it! )

Me