One of the questions that we are asked all the time is "can I claim VAT back that I incurred prior to VAT registration?"
The answer is yes, but VAT can be claimed only on:
services received within six months of the date of registration and used in the business at or post registration;
stock bought for resale if still on hand at the date of registration;
and fixed assets purchased within four years of the date of registration can be claimed in full provided they are still used by the business.