As far as I know, if you're a UK business and you're VAT registered you charge VAT on sales and services regardless. When you start crossing boarders things start to get more complicated. If you sell your UK software to EU countries you still charge standard rate VAT up to £50k per year per country, after which you have to apply for VAT status in that country.

I'm not sure how things work selling software from India but take a look at Revenue and Customs site.


-Steve