fairness,
Forgetting about the upgrading costs etc. that might be a less easy argument to win, do you not have a contract that states where you are based, and if operating away from base on company duty, what expenses the company is liable for? Surely, if your equipment is removed and the company requires you to be retrained, that amounts to being on duty. If the company lays you off and replaces you with with new entrants, that brings in redundancy considerations, not to mention all the other labour law regulations.
However, the on duty away from base expenses should be clear cut. If the company insists you sign away those rights to secure the retraining, that is unreasonable coercion to change contractual conditions of employment for the worse, and would not be by mutual consent.
However, I feel that these laws are only ever enforced when someone sues. When was the last time that happened in your outfit?