Can anyone recommend a ladies wetsuit that would be good for both sea swimming and surfing?

check out mares.com, waterproof.com, hendersonusa.com - they make scuba diving wetsuits, but they are VERY durable and come in various thickness. I am not familiar with the water temp in the UK, but you could get a trilastic wetsuit; it's 7mm in the torso, 5mm on the base of arms and legs and 3mm at the end of the arms and legs (i believe) - this type is good for all sorts of sports. but if you are interested in just one size, i would go with a 5mm wetsuit.