HM Revenue and Customs has made a set of information available on its web site at the Pre-Budget Report 2008 - VAT Rate Changes page including
This won't affect my prices which are quoted ex VAT, but it will be important to account for both 17.5% and 15% rates during the current VAT reporting period.
My personal service company has Quickbooks 8.0 as its book-keeping tool. The number of current sales and purchase items is small, a handful at any one time, so it will be messy but possible to cope with this change without acquiring a new software solution.
With the above approach, the VAT 100 and other VAT reports seem to work fine. It's not sophisticated but it works. Obviously for companies that sell direct to the public, or that have a large number of sales and purchase items, this will become very time consuming and unwieldy. Big companies using sophisticated ERP software such as SAP will be able to implement these changes with timed data, but smaller companies won't have this luxury. And of course, the whole thing will have to be reversed in 13 months' time.