Have a good think about how important this friendship is toyou. Then chose a public place , cafe, swimming pool etc. You could then say how much you value her friendship, but you can see that this could break it up, and you would be sorry to let this happen, so from now on you are not going to discuss it at all . That seems to me a way of showing how much you care about her, and that if that is a no go area to talk about, your friendship may survive. If It does not it is a shame but better than bullied into doing something you dont want to do. Alternatively , let me know and I will ring them up and tell them in no uncertain terms to a) mind their own business b) ask when they can come round to check their house as obviously their house would be better , nay ideal, to use, and watch them retreat!!