Hi Gary,
We are VAT Registered and clean both commercial and domestic customers.
Firstly, as long as you incorporate the 17.5% into your price then thats fine, you can say to a customer is £10 + VAT or just tell them its £12 including VAT (the extra few pence is just for simplicity).
The one thing to consider though is this.
Once you register you are held to STRICT operating terms and conditions. The VAT Office is far more ruthless than the Tax Office and will go through your books with a fine tooth comb.
Make sure you have your VAT money held seperately so you pay your bill each qtr, they don't like waiting for their money!!!
As far as invoicing is concerned, as long as you have them at your end the domestic customer doesn't necessarily need one.
Keep an accurate record of what you spend and your income. This is vital for your inspections.
Make sure ALL your invoicing has your VAT number on them, it is LAW that your number is displayed.
Allthough it makes absolutely NO DIFFERENCE to the standard of work produced, for some bizarre reason larger corporations feel safer the fact that you are registered and seem to lean towards a company that is registered rather than a company who isn't. I think it gives them a sense of stability.
Check this link for all your information and make sure you get a GOOD accountant!
Best wishes,
Trev
http://www.hmrc.gov.uk/briefs/vat/calculating.htm