Personally I would choose May as the Spring flowers will be in bloom and everywhere has that fresh start of season feeling. In May most places will have just opened up, in October most places will still be open but have that end of season feel about them, some may have already closed as half term is at the end of October. You run the risk of showers in both months and cooler evenings. The sea water is still a bit chilly in May, it's still warmish in October.

I cant answer for October, but we went in May half term last year. The temps were in the low 30's, the sea warm enough to swim in most days, some days the temps were higher than that. We did have a couple of days when it was misty/cloudy with a light rain shower, but all in all the weather was good, sunny and bright, with days varying between warm and hot (altho no where near summer temps LOL)

Yes I was there in May last year too. I can cope with it not being as hot as summer temps, last week was tooooo hot for me!

May. I've been in both months and May is preferable as you're more likely to have warm weather. I also find there are less mozzies in the spring than the autumn.

Plus it's nice to be there at the buzz of the start of the season. In October everyone is tired and lots of places are closing for the winter.