I fully support the crew going on strike. Given the low salaries, especially MF, and especially if true that it only applies to the base salary, the offer is a pittance. For London living, it must be challenging to make ends meet.
There is no reason an employer like BA shouldn’t be able to at the very least make a 5% yearly offering given the profits it is making.
Edit: and to be clear, I do have multiple flights booked in August and still support this. Fair pay is incredibly important (to all, and I don’t think it’s fair to point out that some people may have it worse).