In reply to dan bulman: Incidentally I spotted a catch with Jet2 I'd not seen before - they charge you per bag (think it's £16.50) but also charge £12 per passenger who checks in baggage. We usually take 3 bags between 4 on family hols, so normally click the "one bag per passenger" and remove one, which would be £36.
But then I spotted you can check 3 bags in each - avoiding the £12 for two people (you only pay the £12 per person who checks bags in, not per bag). Not a huge amount, but it feels like a small win!