Ideas for somewhere to go in Jan/Feb with 2yo

[MegBusset]

I will (all being well) be 7 months pregnant so will be our last holiday just the three of us. Somewhere within 3 hours' drive of London would be ideal. Obviously weather may be atrocious so needs to be somewhere with lots indoors to do nearby.

Was thinking of a nice family-friendly hotel where DS can have his own separate sleeping area. Can anyone recommend anything?

tia