So, my local Matalan has gone 'unisex' in their changing rooms, and this will be company policy in all stores when they get 'refreshed'.
Doors are not floor to ceiling, and the whole 'changing village' is behind a heavy fire door, so, whole changing area is in another section of the store. I don't think I could summons help if I were attacked. The area is unstaffed.
Men will have unfettered access to changing rooms they know women will use, meaning I will now have the hidden camera paranoia to deal with, not to mention voyeurism and phone pests.
I asked about single sex changing, there was none, but the lady seemed sympathetic to a woman wanting to try on bras needing actual privacy, and showed me the mother and baby room with full length doors, but this isn't a solution in the long run.
I'm going to follow up my in-store complaint, nothing will change, but at least I tried.