Welcome Dee!
What is the reason for that long delay? Unless you signed off on a longer validation period, you are already 11 days outside of your "fixed" tender price and they will (trust me!) hit you with a nice juicy price increase when you eventually get to validation (which for you may still be 3 months away - ie 6 weeks for council approval, then you have to knock down - presume this isn't done yet - etc - as validation not done until after the knockdown done and peg out in!).
See if you can get some price protection in place (if not too late!)
Where are you building? We too knocked down a little brown brick home for the same reasons (and one extra girl - we have 3 of them!)