Nothing like taking something out of time. CSS is now ancient technology - it's still in BT, it runs reliably, but it is a lot of expensively hand-coded Cobol with very limited flexibility built round a very rigid customer model associated with phone lines.
Modern IT systems aren't like that - they are vastly more complex servicing dozens of different types of users in ways inconceivable 25 or more years ago. Scale up the development and hardware budget that was spent on CSS into a new application and the amounts would dwarf the current NHS contracts. Dealing with the NHS was always going to be a nightmare job for any company - remember that there are two IT companies have fallen on their financial swords trying to deliver the NHS system (Fujitsu and Accenture).
Delivering an IT system within the scope of one company and it's various departments is bad enough. If you plug into that the incredibly complex nature of NHS politics, local trusts, independent-minded consultants and so on and capricious politicians and you have a nice little problem. If you want a simple job with the like of the NHS - do a simple job. Stick to looking after the infrastructure. I relative of mine now works for a US outfit looking after the electrical installations in local hospitals, and he says he's never made so much money on soft call-out fees...