Oh Sage lined themselves up for one great opportunity with the VAT rate change. I see that certain lines under General Tax Settings are grayed out, so you cannot change the VAT rate manually. One way to work around this is to create a new "Vat - Standard rated" entry and make that 15%

Is there any other more elegant way of doing this without forcing the client to upgrade to the latest version of Pastel?

As I see it, the new version of Pastel will anyway have two sets of VAT now, one for before 1 April on the old 14% and one new set for 15%. Only drawback is the new version you will be able to continue on tax code 01 for standard rate, but if you want to do it manually, all my clients will have to remember to use tax code 14 and onward from now on, because line 14 on the VAT settings screen is the first available line to enter custom VAT codes.

This rate change is going to be one heck of a pain in the neck for accountants... mark my words... and we have only one month to assist our clients to get this in place. Ridiculous to say the least!