wizard71
Can I point out that I'm not trying to be argumentative, just wondering where the law starts and choice ends
Well, obviously I can't answer for any company, and I wouldn't claim to be A VAT expert, but as I understand it, there's no choice involved. It all basically boils down to whether the vendor is VAT registerable, and complying with UK/EU law or not.
There are two aspects to any law. What the law says, and actually enforcing that law.
If a US company sells services (which is what downloaded software counts as) into the UK then if it sells more than the VAT registration threshold (currently £79,000/year I think) it legally has to register for VAT, charge VAT and pass the VAT on to HMRC. If a company is part of a group/corporation then it may be sufficient for the parent company of the group to be registered and handle all the VAT centrally.
The penalties for not doing so can include fines and seizure of goods or financial assets.
Who the penalty is exacted against depends on who counts as the seller. Which may not be the software company themselves, it may be their publisher or "parent" company in the case of a corporation.
Enforcement is a matter for HMRC. They certainly have gone after software/music/video retailers in the past.
Personally I think we're lucky that software is considered "electronic services" and not "goods". If it were "goods" then we'd have to pay duty as well.