Slowing the stroke was key for me as well - I used to flail away, give myself no chance to time my breathing, and then wonder why I was out of breath at the end of each length. Trying and find a quiet time in the pool and see how slowly and smoothly you can do it - I try and have a song going round inside my head to keep a rhythm going.
Good luck with it - its painful, but it does come - I went through it about four years ago, and my wife did last winter. Completely agree with Dustboy/Soup Dragon above - there suddenly comes a point where it clicks, and you go from struggling to do 4 lengths to 30 very quickly.
Having just entered Outlaw and thinking about what budget I have to throw where, I'd already decided to stay on current road bike just as it is - I'll take familiarity and reliability over gadgets any day.
Vaguely thinking of throwing some money instead at a bike setup - I don't have any particular complaints, but I haven't ever done 112 miles on it, let alone needed to run afterwards. What do people think - worth it or not?
Was a pity - was looking forward to that one, and running past the colleges. Was slightly amused by the person on Facebook suggesting they should have used Jesus Lane lido instead - scheduling 1300 people through even a shortened swim in a narrow lido pool would have been interesting!