Polly
from my reading of the subject elsewhere, then the company propose a single LGW base for SH and LH. The pay structures would see the LGW EF scheduling, salary and allowance base being used, with no CSD's required.
Existing LGW WW cc would have a couple of choices incl moving to LHR WW but remaining on current T&C not an option.
It would appear to be a very popular proposal at LGW SH as they have historically enjoyed a lack of support from BASSA/CC89 re transfer rights to LHR in that they only retain seniority for Staff Travel and lose all seniority and rank gained.
I think it looks like an astute move by the company.
Can you move there? Don't know - where are you now? I'm sure it will be quite popular in certain quarters.