tbf there are pockets of Labour support in certain places. The only remaining Labour councillors in BaNES are in the Paulton/Midsomer Norton area (Twerton in Bath went Lib Dem last time). Bridgwater is a Labour town but the hinterland makes the Bridgwater Westminster seat a Tory shoo in. Wellington is another town that reliably votes Labour, while Frome has been voting Green lately and has a town council controlled by independents.
But the farmers, landowners and moneyed retirees etc keep the Westminster seats in the blue column by and large
Edit: in Gloucestershire, the Stroud seat has been Labour often enough, the towns of Dursley, Stonehouse, Nailsworth and Stroud itself being a match for the Cotswold set. Gloucester is a working class city that Labour really ought to win more often than they do, while the Forest of Dean has a decent Labour vote (or used to at any rate - still strong in Cinderford, Coleford & Lydbrook)