Asked for a call back if those prices are legit I'm punting the 30 and the bits, apr will remap and remove the map for services happy days 
will this not invalidate your insurance? Cant mod a lease car surely...
In terms of why they are doing it it is as per your comments and those of Paul - they get a load of stock back in pre registered in 2 years time with only 20k on the clock and can then sell them on at reasonable prices.
Dont forget the R is a very niche car - chavs cant afford them and those executives/self employed people who can afford to lease £30k+ cars aspire to a better car than a golf - they want a 4x4, merc, 530d etc etc
I think i would be very tempted accept not got time to strip the eddie as just bought new house in need of serious renovation and if im being honest i need a bigger car than a Golf next