Managing your VAT obligations can be quite a hard task especially if your just starting out. Might be worth looking into a reliable software to help manage all this. I did the same when I started my business. There are quite a few on the market but as your business starts to grow and if you ever start providing your services into other countries in the EU you would have a different VAT threshold for that which means it wont be the standard UK 20%. There is a cross border VAT software that might be useful for this and I believe it also notifies you as and when you need to register for VAT in a particular country too. Apparently there is no other software that does that. Anyways hope this helps 
The independent UK VAT forum