It's funny, isn't it... the responses here are so different, which surprises me. We're in the process of house-hunting and almost made an offer on a place which had beautiful interiors, including curtains I would definitely have wanted to keep, as well as their unusually-sized fridge freezer.
The value of an item has not so much to do with what you paid for it and whether it's depreciated as the cost and bother of replacing it. I would be gutted if you took the FF as I'd be viewing the cost of a fridge as an annoying extra expense.
Re. the blinds/curtains, this will be a tradeoff between how much they like them and the cost of replacing. Sometimes you don't much like something but can't face the ball-ache of turning up to a new house without any fixtures/fittings, and it taking a while to get things up and running. This part of the negotiation can get very fraught, but it is normal to have to negotiate at this point and doesn't mark you out as being mean! Be prepared to accept quite low prices, especially for the curtains, as IMO they might like them but still won't be curtains they chose themselves - my own take on it is that if the vendors want too much money for them, I might as well get something I've actually chosen myself.
To answer your question, I'd expect something like £250 for the fridge, peanuts for the chandelier, and maybe £300-400 all in for the curtains/blinds. And if you got offered that I think you should take it, removing the stuff when you've been offered money for it is NOT a good move!