Admittedly, I have skim read most of the thread, but as an NHS nurse, I can assure you we want elective work back as much as everyone else.
Within days, our dept (operating theatre) was turned into a makeshift ITU and the majority of our staff were redeployed. Those of us left have covered the 24/7 emergency theatres. The number of staff to cover these had to increase as general anaesthetics are ‘aerosol generating procedures‘ which entail donning full PPE and needing extra staff as ‘outside runners’.
Testing was introduce far too late so lots of staff were off for 7 or 14 days self isolation. Staff who did catch the virus were off for much longer as they were too weak to return to work. We sadly lost a member of staff to the disease just this week.
So, in response to an earlier post, the ‘other‘ departments couldn’t possibly have carried on functioning. 
Apart from emergencies, we did have one functioning theatre for very urgent surgery, which was well utilised and other urgent work has been shipped out to some of the private hospitals nearby.
Very slowly, our dept is starting to look more normal, and elective patients are being swabbed with a view to start surgery over the next couple of weeks.
With regards to the Nightingale hospitals, I do know that a junior dr relative was to be seconded to the one.
So, I can only assume that surrounding hospitals would have been depleted further in order to staff those.
I hope those of you who are awaiting treatment get it very soon. 