Is it legal for her to draw down my cheque as I am now paying the mortgage interest without having a house?
Heres the problem. Its not your money - its the banks. She cannot close the transaction until she can be sure that everything she needs to do to comply with all of her requirements to your lender are in order e.g. searches etc.,etc. It could be (?) that your builders solicitor does not have all the requisite paperwork in place to close.
Now, if everything is in place then she should be able to close but to do that she needs the funds. In the ideal world, the solicitor would simply call the lender when everything was in place, they would get an immediate transfer and you would then close. ln reality, and from bitter experience I can tell you , the solicitor can end up chasing chasing chasing funds, being hounded by builders solicitors and purchasers alike, to find out if the funds are available ( not "on their way" ) to set up a closing. I can only do a closing 24 hours after receipt of funds to give time to set up searches.
So its a choice - leave funds to last possible moment and run risk of giving over the entire day to chasing them for one client or get them in advance to be properly organised.
Check with her that its only searches that need doing and nothing else. If it is just searches, then she should be able to do it now.
mf