I am going back to BA in June after nearly 10 years away and can't wait. I found some of my payslips from when I was on LGW WW back in 1998 - basic salary was over £16,000 and average take home pay was around £1800 and that was as a grade 1 with 9 years service. Thinking back to those days were we happy then? Most of the time yes but we still moaned about pay and conditions compared to LHR and how hard it was (10 day Seychelles, 10 day Dubai's, Back to back Antigua - more like a holiday). I left to try other things and trust me it has been a hard slog. I have worked in management positions and also had my own business and worked 80 hours a week with no days off and earnt nowhere near as much as I was back in 1998. Having run my own business I have had to make cut backs and changes that weren't to everyone's liking but what was the alternative...go out of business and nobody would have a job. If I were running a company like BA I would do the same thing to cut costs and remain in business.
I am fully aware of pay and conditions at LGW now and I am still really excited to go back. No more 80 hour weeks only to give most of it to the tax man and pay other bills.
I had interviews lined up with other airlines but chose BA as I think they are the best.
I think that terms and conditions at LHR will eventually be the same as they are at LGW. How they will do it is anyone's guess but it will be done as people on the better contracts will leave eventually or take a pay off to leave and be replaced (I took severance back in 1998 and it was well worth my while to take it).
As someone who has been on the "other side" it isn't any better outside of BA - fortunately I have been given the chance to go back to a job that I have missed desperately for many years.