Thanks for your reply,
The reason that I had a coaching session was that after swimming in open water for some months and on returning to the pool I saw that I had a high stroke count compared to my green zone which should be 14-18.
I was in the low twenties and I reasoned that this must be why I was so slow to others that I swim with.
I thought that I needed to work on this so I got the latest of Terry's material and went through step by step which gave me marginal improvement.
After that I went for coaching and there were some hip drive issues which I believe I have fixed and with extreme focus I could make 18 SPL but not consistently.
Back in open water now and the other day did a time trial where I did 2k in an hour even though I felt my stroke was good. By this means that I go through the water easily with little wasted effort and splash and can easily do 3-4 km.
For the last couple of days I have upped my stroke rate, swim with more rhythm and try to take any pauses out of my stroke and according to Mr Garmin my 100 rate for yesterdays swim averaged out to 2:7.