In IMUK recently, there was a guy near me that I kept overtaking as he was breaststroking for a minute in every five or so. It p*ssed me off after a while and I finally left him behind!!
I couldn't swim f/c a year ago and nearly drowned every time I tried until I slllooooowwwwed right down. Once I'd done that, breathing became easy and within two weeks I could do 100 lengths no probs. Then comes the speed. No lessons, just sensible stuff.
Good luck and remember that the swim's just a mild inconvenience to get you to the start...
I couldn't bring myself to part with the dollar. Cheap it ain't! Mrs LoR nearly had a heart attack when she saw how much IMUK was just to enter, so she wouldn't have taken kindly to a familiarisation weekend.