Uggh, so much naivety
'cannot migrate neither to another version of Windows or upgraded to Linux as the vendor is not around any more' Yep, and that will also apply to the NHS, perhap more so, as they dont have money to replace old capital equipment.
NhsBuntu? Oh yes, absolutely, of course, it makes complete sense. For purely altruistic reasons, we all love a bit of FOSS on the side. Make money from it?, No, thats they other chaps, the evil vendors. Bad vendors! We are develpoers, we'll do it because we 'heart' the NHS. Current budget is Hundreds of billions you say? Right, well, thinking about it a bit more, we probably will have to charge you somethign for it.. might be quite a bit actually, less than the other evil vendors, of course, but yes, might cost a bit at the end of the day...