The exterior is glorious, you've done beautiful work on the garden. But I do agree with previous posters about the interior.
When we buy, hopefully soon, we're going to be stretching ourselves, and we're not going to have spare cash for redoing everything, and I would guess that a family that are selling a house to buy this one are still going to be in the same position, even if they too have done well out of the housing market.
I think you need to position the interior so it doesn't look as if it needs everything doing to it to make it more modern; e.g. with the bathroom, you'd do well to just paint the whole thing a nice pale cream, to tone down the browns a lot. If you could replace that side panel too, and the loo seat, it would look a lot more modern.
The rest of the rooms have more modern interior decoration, but the furniture is possibly making it look less so? I quite like it but a lot wouldn't.
For the kitchen, it's very smart, but that black and white look is a little bit much - but you could tone it down a lot by replacing the black handles with white ones.
That said: prices in London are dropping a lot. I think you do need to reduce it by a good chunk.
Good luck with your sale, I hope this thread helps - and that bedspread and matching pillows are darling, I think they're really lovely. (Though, again, whilst I love them, I'm not sure they're really a modern go-getting look, and I suspect that a family who can afford your house would want that).