Ok got some prices from YB racing today:
6 point bolt in cages with door bars that need welding in after installation, and single cross member in the rear.
Model AA/104P/154 To fit Mk2's (they say including the Synchro) 5+ Cages £321.45each plus 18.95 delivery
(Their ebay price is £394.95 plus 19.99 delivery)
Model AB/105P/156 To Fit Mk3's £300each plus 18.95 delivery
(Ebay price is £349.95 plus 19.99 delivery)
Delivery will be in the region of upto 6 weeks.
Cheers
Paul