Re: Cost is the smaller concern
"For the NHS cost is the biggest concern and will become increasingly so."
When working in NHS county level IM&T the biggest concern was avoiding generating "clinical risk" (ie bodies) as a result of IT failures.
Seriously, most IT professionals really don't care which OS systems run on as long as the required software runs on that OS. SystmOne & EMIS are web based now anyway so they should be good enough for a wide swathe of healthcare applications.