At the end of the day, BA is trying everything to intimidate their staff, shouldn’t they try to solve the issue in the first place?
As I understand, the perks (which in fact are a good money making scheme for all airlines as it helps them filling empty seats) are discretionary.
However, it is illegal to punish staff for participating in a legal strike, and by removing staff travel to those who were in the strike, BA is in effect punishing those staff.
(therefore acting illegally)
If the company decided to remove staff travel, then they should do so for everybody not just to those who were legally striking.