Citing Red Rat in part:
The UK remains the only ally who can put a division in the field with the Americans and is technically more integrated than the other "Five Eyes" partners.
Chatting with a "lurker" with military expertise they remarked the current emphasis on the UK contributing at divisional level meant the one UK division that can be deployed MUST be when an overwhelmingly national interest is at stake. Plus there isno follow-on division.

Secondly I do wonder if NATO decides it must have forces deployed forward in Eastern Europe, Poland notably, will the UK actually totally exit from Germany? Rotating from established bases in Germany is far better than other options.