With no answer all this time, and being an ex-FCA employee, I'll have a stab at it from a purely personal opinion.
Having read in trade press that many FCA aircraft are likely to be returned off Lease within the next five years, and having seen (in other fleets) leases being curtailed or transferred at the drop of a hat, and that the combined TUI/FCA B787 orders total some 23 aircraft, I think it likely that FCA at CWH will be a proposed closure, possibly retaining Line Maintenance at locations not co-located with thomsonfly and merging those that are located with T'fly.
T'fly at LTN are a much larger engineering concern and with a Base Maintenance factility and probably preferred by TUI Head Office.
As I said this is personal opinion and, obviously, I stand to be corrected or otherwise argued against.