although it’d make me cross if NHS equipment was being hijacked for this
Once again, apologies for being way off topic, but this isn’t really how it is. Taking the example of an MRI scanner, for example many of these are privately owned and / or operated. It goes something like this:
Private company puts in a scanner and employs radiographers, admin staff etc. Hospital contracts with private provider to provide scanning service – the contractual form will vary from place to place, but they might contract for x scans per month, or X hours availability with a minimum of Y scans. The private company can then use the scanner and staff for whatever it likes on top / outside those hours.
This is one reason why private patients can get easier access to times that suit those in work – the scanner might be exclusively doing NHS work from 9-5 but the company has the unit open from 6am – 10pm with the private patients getting the early morning and evening slots.
The company makes profit on those scans (the per scan area price to BUPA is unsurprisingly a little different to what the NHS is paying), so the NHS can benefit as the amount the company has to charge the NHS and still make it’s profit is considerably less than it would be if they did the NHS work exclusively.
The hospital then has more money for other things, or indeed for more scans.