A lot of of the key stuff is covered above. However, doesn;t matter how cold it is you can work up a sweat getting kitted up - particularly if you do have a good undersuiit. Essential therefore to have a good thin base layer that wicks moisture away to keep you dry otherwise you will feel the cold quickly if wet against your skin.
Fourth Element xerotherm and
EDZ base layer work well....along with a host of others. Their sock are also great under conventional ski socks - keeps feet warm and dry.
The
Xerotherm Arctic is an even warmer option if the undersuit is not at good as it used to be.
Weezels - you either love them or hate them..some people find they are too fluffy and retain a lot of air on ascent...tricky if your bouyancy is right on the edge and carrying minimum lead. Conventional thinsulate suits..200 gram.. are a viable alternative. There is an article on these suits in March edition of Dive magazine.
Have had mixed success with dry gloves - great if they work but have had crushed hand when the equalisation didnt work and flooded suit when seals didnt work! Been using the 5mm
"Waterproof" semi-dry gloves from Sweden this winter and love them.
Use same hood the year round..came with my Otter Suit...has bare neoprene around the face to prevent flushing. Never felt cold around my head.
If your suit has latex neck seal, wearing a scarf or small towel around your neck can cut down heat loss there.
Where will you be diving? Stoney Cove can be a lot colder than that!!
Steve