New Build.
You can claim your VAT back on completion, on materials, but not on plant hire, lorry hire, tool hire or scaffold hire. The way round that is to employ a VAT ground worker, who will pay his VAT and claim it back in the normal manner but he will not charge you VAT on a new build house. The same goes for the scaffolder and any other trades you employ that are VAT registered.
Would suggest that you do an NHBC Solo to obtain a NHBC certificate. Also do your building Regs with NHBC at the same time. Makes life a lot easier.
HM Customs and Excise.
You should be hit with CGT, but if the same 3 year rule still, applies that we have worked to in the past, you are in a fortunate position that the land you are building on is owned by you, then there are ways round this that could overcome CGT or reduce it a to an easily affordable amount. Would take me to long to explain on here, but a good accountant will be able to explain it to you. It all revolves round your main residence and part of your garden.
Regards oldun