Well, I finally decided to get a new wetsuit!
I managed to ebay my old surfing one and have rented a Foor Classic from TriUk http://www.triuk.com/products/foor/foor-classic#.VUIavpQ2w_s
I spent ages looking and decided to go for this because it had some 5mm panels to help me float. I am expecting a massive difference in comparison to my old one.
My local open water venue opens next week, so I am planning in testing. Will report back then.