BA does not work 4/3 or anything of that nature. Bidline rules currently give you a minimum 2 days off after a long haul trip, or you’ll get EASA rest if that requires longer. Bidline days off can be waived when bidding, but EASA obviously cannot (although you can bid for back to backs as long as you pay for and use the company supplied hotel). When you bid, you can request more days off, but that does not mean you will get them.
People regularly ask for typical rosters on here, but typical rosters do not really exist because they very much depend upon seniority. Typically, I would say new entrants can expect a trip then two days off, continuously, with the odd three days off perhaps once every month or two. The frequency of two days off in between trips depends on fleet, monthly CAP and the credit/length of the trips you are managing to pick up. If you work on 2 days off all the time, you might be pleasantly surprised and do a little bit better than that, but in order to join with your eyes open, you need to assume just two days off is typical or you will almost certainly be disappointed with your move.