The Tweed Repository

Cirencester is probably a better bet - possibly a bit small, but its closer and quite the Landed Gentry kind of place and also has an agricultural college - bound to be masses of tweed :)

Cirencester makes Gloucester look like New York City and actual landed gentry would wear use their tweed.

Cheltenham for those with too much money who want to look like landed gentry once a year and then donate it all to charity.