I've seen several SH 320 rosters for both LGW and LHR across winter and summer and they're again appalling at times.
An example of a friend who is LHR 320 this month from Roster Buster:
Day 1-7 on night stopping every night, off 8-9, 10-11 on (day trips), 12-13 off, 14-15 on (day trips), 16-17 off, 18-19 on night stopping, 20 off, 21-27 on night stopping every night. Here take day to mean within what I can see of the roster, not date.
That's after 3 and a bit years in the company - working every weekend. I'd rather bunch my stuff together and have proper blocks off, not night stop and get my fair share of weekends off. Call me a boring weirdo for enjoying family/ friend time by all means but BA are in fact TOO stuck in the 60s in many respects. I wouldn't invest my time in a company in this way on the basis of a promise later - which without a shadow of doubt will not be delivered.