Hickdive
Contributor
Still just 5.5mm on the legs and arms though, waaayyyy too thin IMO. At 10m your body will be covered with 5.5mm and arms and legs with just 2.75mm! We used to have a saying in my club, 'Buy a wetsuit and in six months you'll either give up diving or buy a drysuit'. Either way you've made an expensive mistake.
Don't forget that in the UK it is only occasionally that the weather is warm enough to sit around comfortably in a wetsuit when out of the water. This is actually often more of the problem with wetsuits than their in-water warmth. It is easy to be relatively comfortable during the first dive but become progressively chilled when sitting around during the surface interval to the point that you don't get a second dive or the second dive is seriously curtailed because you're now too cold.
The alternative, taking the wetsuit off and putting on dry clothes between dives leaves you with the prospect of stripping off again and putting on your now cold, wet, wetsuit on. Wet skin + wet wetsuit = relatively easy to don the suit, dry skin + dry wetsuit = easy to don the suit, dry skin + wet wetsuit = bloody nightmare!
However, if you've still got your heart set on buying a wetsuit then I suggest you also purchase a big, cheap, insulated and waterproof jacket, a good woolly hat and surface mittens (warmer than gloves) and put them on as soon as you can, over the wetsuit, after each dive even if the weather seems relatively benign. That will save you having to strip between dives. If you get too warm you can always take off the hat, mittens, and jacket progressively to cool down but it is much, much harder to re-warm yourself if you've become cold in your wetsuit. Hot food and drinks after the first dive can also make the prospect of a second more enticing too.
