There is only one life jacket worth getting and that is a life
RAFT.
But on jackets, nearly all those on UK sale are made by a firm called Remploy, and they make them up to slightly different specs of external fabric according to what each aviation shop wants to pay for it.
I recall, from years ago, that the Transair ones were slightly more expensive because they used a less sweaty kind of fabric, and having 3 of the latter and 1 with the sweaty fabric I would say that they are worth the extra tenner or two.
Currently, I would consider contacting SEMS in Basildon; I believe they sell this stuff too (they certainly overhaul them) and they should offer various options.
There are some very classy US made jackets but are hard to buy here in the UK - check out
Svitlik