Re: TCAS requirements?
I understood that all aircraft with over 19 seats or a certain weight limit must carry TCAS II (or rather ACAS II) in En-Route and controlled TMA airspace throughout the vast majority of Europe if not all (although, it is the responsibility of the Air Traffic Service Providers to issue to AIC mandates for carriage). It may even be more stringent than that. All exemptions as far as I was aware expired on 31st March 2001 so everyone of a particular size should have TCAS II by now. The UK mandate is available somewhere on the CAA web-site for soft copy download.