I remember from when I applied that they were very hot on LSAP being payable on your first house only and to make sure you had the LSAP in the bag and with your solicitor before you complete, or you would be deemed to be a property owner already and it would all go horribly wrong. It might be worth checking with them if that rule still applies.
I saw an AMP Presentation a few weeks ago and they were talking about upping the rate considerably, and making it a retention bonus rather than a loan. They were a bit short on detail about how much and how many years etc, but a bung would be nice (my LSAP at £8500 buys the doorknob on a modest semi in Albertshire
).