I think the T3 queues are actually worse than they look. I hate the place, the low ceilings and ridiculous narrow corridor to departures are horrible. There space is long and very narrow, there isn't a lot of space for more than one "turn-back" around a TENSA barrier, so queues could be shorter than they look. T1 has a huge TENSA holding pen - although I've never seen that full myself. T1 also has far more lanes, T3 never seems to have enough. I think more people tend to arrive later on the flyBe and BA services, so the constant calling of flights and people fighting through bodies probably makes the perceived experience worse than it really is.