I just wanted, having had a lot of support here, to let people know (having read a lot of very unhappy threads about house hunting in London, that sometimes it does all work out ok.
We originally accepted an offer on our place in SE27 in October last year for full asking price. That buyer pulled out within two weeks, but luckily, another buyer came in at 2k under asking from the same open day. We dropped a further 18k on survey (prices in our area have gone bananas, and we still did ok). They had terrible trouble with their mortgage company which in a way is just as well...
This doesn't include the 30+ offers which were not accepted.
Offer #1 - a large 2 bed place in SE19 - had an offer accepted and survey done (costs of £900 lost on this place), couldn't proceed as the elderly disabled vendor couldn't find a place to move to - wasted 2 months on this before EA fessed up;
Offer #2 - a nice 3 bed in SE10 - turned out the sellers were a divorcing couple and she had no intention of moving out, despite having met us on the open day - three months wasted on this along with £2,500;
Offer #3 - a three bed in SE23 - beautiful, and finally with vendors who seemed to want to move out. On exchange day, today, we found out they had lied about £7.5k of outstanding leasehold works which had been done (new windows) and tried to stiff us with the bill. We told them no way and they buckled at 4.55 so finally, finally have proceeded to exchange (another £3k in surveys and legal fees on this place).
So while it's been a hugely frustrating and stressful 10 months (we move next Tuesday) it has finally turned out for the best, and property 3 is far, far nicer than the other two. OK, we've lost a bit of money, but with the way the market is going in London, we'll make that back in a lot less than a year. We're ending up in the right place, our buyers were hugely patient and willing to put up with a mortgage offer extension to enable us to do it (having also lost out on 3 places themselves) and both DH and I now have far better commutes than where we are moving from, and finally have the room to start TTC properly knowing we won't have to move again.
Just thought people might like to hear a happy ending!