I know little about the UK's ATC systems. However, occasionally (no more than once a year) we see a system failure that means the chaps have to revert to a manual mode. If we look ahead to the two centres (Swanwick & Prestwick) working on the same platforms, surely it would be worthwhile having two separately procured sets of software working in parallel (something akin to the airliner separately developed engine control programs)?
No criticisms, just a bit of sat-at-home-slippers-on thinking.