Buying off plan means you should get some input when it comes to speccing your home out. So you can have that kitchen that you've always wanted or extra plugs sockets etc... you get what I'm trying to say. As for your mortgage and searches expirying I cant help you with that. I was going thru a off plan purchase with DW but pulled out (see weight restriction thread

) I was part ex'ing my old house so as for completion I would just stay in may old house until the new was ready. If you can try to get a date when you should be in by. Dont think they'll give your an actual day but try to nail em down to begining/end of month. And as for you completing with 28 days thats bull dont listen. There just trying to tie you in. Once you sign and exchange the contracts you are legalaly tied in. I reserved my plot on june 16th was told must exchange by july 16th or I will loose the plot plus my reservation fee £250. This date came and went as I was not getting any answers on fittings for the house. Not at anytime after the 16th of july did anybody ring to push thru the contracts. Oh and another thing they can change sizes and dimensions at anytime without telling you! this will all be the your contract that your solicitor will send you but bear in mind like I said that as soon and the contracts are exchange your tied in, you can still get out but the developer may charge you to do so. Also there's also stages of the build that you have to beaware of. Once your house is past a certain build stage it's to late to choose the extras that you may have wanted, sometimes they will have to end off for prices for things as the sales staff sometimes dont have all the info. In DW's case quates took about a week (wanted extra cupboads and wooktop in kitchen) so bear that in mind. Remember the developer should help you, your doing them a favour by buying one of there houses so dont feel pressured into signing if you dont have all the right info. You'll regret it if you sign without knowing something then it turns bad after. Luckily I got out before signing so I just lost a small amount of money. Apart from that enjoy your new house in 8 months time.
cheers