First off, for your rental, try
Wotif.com: Hotels, Accommodation, Motels, Serviced Apartments, B&B - Online hotel bookings with instant confirmation and get a short term holiday let which will give you time to find a longer term rental in an area you like.
New builds - we are in the process at the mo,
First bit of advice would be don't use Dixon Homes, they have been on the telly and absolutely slated coz they can't deliver the goods as promised.
Yes, new builds qualify for first time homes owners grant once house is built I think (I've actually forgotten what they said about that coz there's so much to organise).
There are risks of course - basically the cost running away from you. Most reputable 'project home' builders will give you a fixed price for work however not many include things like basic landscaping (turf), fencing etc and the price they give you in their leaflets i.e. starting from $xxxxxxx - be prepared, that will very easily shoot up $50 to $100k coz that price is basic house no frills on the perfect piece of land which almost certainly doesn't exist.
Yes, you can get a mortgage on these (assuming you qualify in all other areas) no problem at all. They will take around a year to build from initial consultations/agreement to handover and be prepared for the fact that you will be paying both rent and mortgage during that time - the mortgage being released in stages of house building process.
Check out some of the display homes dotted around in 'display villages' (display villages are nothing more than a street or 2 of display homes on new development areas)
Lyn x