Here we go again re-inventing the wheel. I flew for the Met for several years in the early 80's and they had trialed fixed-wing operations and found that they had limited availability and poor response time, so they went for helicopters. It seems that the new NPAS has sacrificed response for "notional coverage" so no problem there for most of the country but I see why the MET are dragging their heels on joining. They don't want a watered down service.
Fixed-wing certainly do not meet the capability of heliteli surveillance in inner city ops. Try keeping eyes-on in a Regent Street demonstration in a plank- 2G 60 degree high power noisy turns over the inner city!
All the deficiencies being created with this programme will need to be covered direct from government on ther first occasion there is a national incident. What a waste of time, effort and money, and more importantly the lost experience of the local operators.