Check for Hot Escapes specials, although these don't become available very fasr in advance and are nonrefundable rates. They can also sell out fast, so it could be difficult to coordinate with flights available for Avios.

Otherwise, think of nice hotels in business-oriented cities. Brussels and Frankfurt are examples. Athens might be cheap now. Other countries in Eastern Europe can be cheap. However, personally I'd think twice about going someplace that's being overwhelmed by the immigrant crisis.