Hi Grizzly
Don't know if Basingstoke is too far for you to travel but they have a Slaters Menswear branch there (I think thats the closest one to Southampton) as well as others throughout Britain.
I purchased a made to measure tweed jacket and waistcoat from the Glasgow branch recently at a cost of £240. I am 48" chest. They have several pattern books for you to chose from.

The beauty of having it made to order is that you can choose your own style of sleeve cuff, epaulette etc., or do without.
Give them a call.
Cheers
Eck