My local pool has one wide lane for laps*, so there's generally room to overtake, it's the just the people who insist on swimming one centimetre from the middle of the lane that get my goat. It's always the same ones who don't let you turn at the ends either. That's why I have the shark in the first place.
The lanes at Crystal Palace where I also swim are relatively wide, there's room for one person to overtake, and generally speeds are well matched (there's usually one slow, two medium lanes, and one fast). I think the 50m length sends most of the dabblers to the kids/training pool.
Thirty-three metre pools must be rare these days – the only one I remember is Ladywell (now no more, knocked down to sell off the land to developers, replaced with the generic one in Lewisham). Bit of an odd length, but I quite liked them. I always find 25m too short. It was the Ladywell pool that got me back on a bike, to avoid the walk there and back each lunchtime.
*they do slow/med/fast lanes in the morning and late evenings, but I mostly avoid as they're narrow, full of OAPs, and I can't be bothered getting up that early.
