Vera, you may have some bits right, either by assumption or knowledge, but there could be merit in some "filling-in".
Whilst the proposal may be to put the South East region together, this actually includes the remaining aircraft in East Anglia, namely the current Essex & Suffolk machines, as well as Benson and (for the moment) Henlow. Essex have been policing the whole of Kent from the air since early 2008, as I understand it, with backup from Suffolk or Cambridge when the Essex aircraft is unavailable. The new, even-more-borderless proposal is that whichever aircraft is closest should attend, so you may find the current Sussex or Hants machine attending Southern or Western Kent.
I also understand that the Southend option would appear to be off the cards for the moment, so Kent would continue to be serviced from the current Essex base, or I believe there's also a base at Rochester.
I'm a little unsure where you got the impression that NPAS was planning to become a one-type fleet, as it's not been in anything I've seen. The original plan, as I understood it, was to have a couple of 135 spares & one 902, to cover the country. The co-ordination of that will be fun, whatever happens, & those without either type will have to haul in assistance from elsewhere, I imagine!!