Celtic- congratulations. How long has it been from putting an offer in to getting the keys? When are you going to move in?
Lepaskilf- what a PITA about them demanding indeminities. As for when to pay deposits etc, it all depends on what the rental market is like near you. If you have a rental market with not much coming on and what does come on goes quickly, it might be worth paying deposits etc before contracts are signed. If there are a lot of suitable properties near you then you can afford to wait.
Update on ours- we have begrudgingly knocked some money off, including for items that irritate me. For example we've had to knock off money as we don't have a consumer unit, however made sure that this was highlighted on both viewings, so offers were made with that in mind. We couldn't risk loosing the sale, and the purchasers building society put ridiculous retainers on the valuation (although they did agree to remove the one for the sump, just incase the new owners wanted to convert the basement into a usable room). We are nearly at a point of discussing dates to exchange.