Sorry, I don’t think I ever replied.
The biggest improvement came from going from 2 - 3 times a week to 4 to 5.
A lot of time commitment but going regularly makes a big difference, was not really getting far before this.
Currently going 3 times a week, less frequently 4, consistently session to session is better / good, much slower improvements, but still there.
I’ve entered IM Swansea 70.3 July 2024, hope to transfer some pool swimming to OW but its hard because I hate OW 95% of the time, it’s the cold and openness that scares me, plus I don’t like the floaty wetsuit, it makes me off balance. Think I have fixed that though as I can now swim better with a pull buoy, occasionally it would make me almost flip, not any more, winter so not had chance to try OW and see.