Just because it's possible, doesn't mean it's a good idea.
I would not consider diving in a wetsuit in the UK. Give me a leaky drysuit - with fourth element Arctics or similar decent undergarments - any day.
A reputable PADI outfit will put you in a drysuit before you go diving outdoors. Often they will arrange your OW dives in such a way that you can get the drysuit "specialty" for a relatively small fee if you want it (ie for renting drysuits elsewhere).
Sent from my HTC One SV using Tapatalk
Would have to be AOW as I already have the OW cert. Guess it might be possible to do AOW with dry as one of the specialities which would mean the pool try out session would be the only add on.