Skyseeker
No you made exactly the right choice! OK, if you play the probability odds then you could have gone and been 70% OK!!? However, if the 30% probability did happen then you could have been in serious trouble.
I am afraid its one of the frustrations of the UK isn't it and this particular type of weather.
As they say, better to be on the ground wishing you had gone, than having gone and wishing your were on the ground!
Don't let any one persuade you to start taking chances with this type of TAF
Well done!