B&Bs and Independent/Family Run

Vrbo, OneFineStay, PlumGuide.

Premier Inns

https://www.bestboutiquehotelsworldwide.com/towns/best-hotels-london-england?gclid=EAIaIQobChMIuumCqdTu_AIVJBV9Ch3LLwHoEAAYAyAAEgJxIfD_BwE

Just google ‘B&B Cotswolds’ - you can easily tell which are the small, independent places, many of them in the owners’ houses . Actual B&Bs in London are likely to be out in the suburbs so there I’d look for a hotel.

Rick Steves guidebooks generally recommend that type of lodging. That's the first place I look.

I use booking.com. It lets you narrow lodging by type (e.g, B&B's), and you get reviews written by people who actually stayed at the establishment.

For something different have a look at the rental cottages offered by the National Trust, especially in the Cotswolds. nationaltrust.org.uk

Our stay at Manor Close in Bourton on the Water was lovely. Joe and Sheena were terrific hosts. https://www.manorclosebourton.co.uk/