Boy oh boy, well KLM mainline pilots, you have proved that that has been said for a while, you are ARROGANT and totally selfish.
Most of the KLMuk pilots have NO interest WHATSOEVER in flying your mainline aircraft, those that wanted to fly longhaul have or will leave to join far better airlines in the UK.
It might be well for you to consider EU law and the fact that your current "regional partner" ie KLC has full seniority within KLM ML.
BY creating a single seniority list when you integratated the KLC pilots some time ago onto the mainline list you set the rules, therefore any merger of KLC and KLMuk with the pilots from the UK being put at the bottom of the combined list would SEVERELY disadvantage the KLMuk pilots therefore be ILLEGAL.
The only solution is to create a seperate list for your "regional division" by combining KLC and KLMuk pilots by joining date, but i am sure the KLC pilots wouldnt accept being removed from the main list.
KLMuk represent less that 10% of the total KLM workforce so any disadvantage to KLM or KLC mainline pilots would be minimal anyway.