I've just got back from a long weekend doing trimix dives in Spain. I flew over with BA and they've made an interesting change to their baggage policy. Hand luggage is now allowed to weigh up to 23kgs as long as you can lift it unaided into the overhead lockers. So with that and my 23kgs of hold luggage, I was able to take out four sets of regs, a drysuit, a stainless steel backplate and all the rest of my dive kit. I even had room for non-essential items such as clothes. So definitely a good option and of course food and drinks are included onboard. You might just need to hit the gym to make sure you can lift your own bags.