And to add to John's post -
The money is OK, but beware of the posting they offer you, the islands - including Sumburgh and Kirkwall are very quiet, the others even quieter!
You won't get Inverness unless you know something which hangs in either the airport managers or the Manger ATS closets (information available at a price
).
Whatever you do,
do not buy a house unless it is in the Inverness area, equally think very carefully about uprooting family. Shetland (Sumburgh or Kirkwall) is not a good family prospect.
Negotiate trips home - at least one per month fully expensed flights etc.
The jobs a piece of cake, quality of life is pretty good, standard of education very good, but you've really got think about what you want to get out of it and whether you'd be happy working at quiet stations for the rest of your career.
If HIA ATC does go to SERCO, although TUPE does cover a lot, it doesn't cover pensions, and the CAA pension fund will not necessarily allow new or existing members to remain in the scheme.