I was in Bicester village (outlet centre) on Saturday, just off the M40, they have Helly Hanson Drysuites reduced from £399 to £99, be careful as some are marked up as £149 so get the ones with the £99 tag on

These are NOT the breathable ones but are good value for money. They have the rubber ankles (not boots, although there are some oftem there as well), cuffs and neck seal. LOvely colour with a front zip but no convenience (fly) zip, so I guess you pays your money and takes your chance
They are in the back left hand side of the shop, if you are feeling really flush they have an ocean flotation survival suite for some ridiculous amount of money, reduced from say £899 to £400 or so, may be of use to certain individuals on here
There is also a Musto shop that has some very smart drysuites and survival suits, although a bit more expensive.
I hope it is of help to someone, but with winter coming and the rush on these drysuits don't hang about, apparently it is the fashion, nearly everyone in Bicester walks around in them now