Just to add my 2p in on this rather old topic :-)
I'm currently at the College in Bournemouth and in covering CAT II/III ops recently, Mode S came up. As many have already stated, UK does not currently have the equipment to accomodate Mode S transponders...not heard anything either on when they expect to have the gear upgraded.
Consequently, it means the UK has no CAT IIIc ops as the requirements are to complete a fully automated landing, rollout, vacate runway, and automated taxi...still would love to know how this can work - hopefully someone with experience can explain? Is the aircraft taxied using FMC points in co-ordination with transponder Mode S for GMC surveillance?
Would love to see this demonstrated - would bring a whole new meaning to "zero vis procedures"!!!
All the best,
Chris