Hi,
Looks like the clock's ticking for you on this one!
The quickest way to do this would be to run a SQL query to update all product prices en-mass but proceed with extreme caution and backup everything beforehand.
***Important disclaimer***
Please run the SQL below at your own risk. Run on a development database before you run it on a live system. I have just written this quickly for you and it's not tested fully, no guarantee or liability etc etc....
This SQL is based on the situation where all your taxable products are rated at 17.5% and stored in ASPDotNetStorefront excluding VAT. It should update all taxable products so that when the new 20% VAT rate is applied, the gross price remains the same.
For example:
Current product price shown to the customer: £10.00
At 17.5% VAT, product price is stored in the ASPDotNetStorefront database as £8.5106
After running the script, the database value is now £8.3333
Once the VAT rate is changed to 20%, this displays to the customer as £10.00
OK, here's the SQL...
Code:
update ProductVariant
set Price = ((Price*1.175)/120)*100
where IsTaxable = 1
update ProductVariant
set SalePrice = ((SalePrice*1.175)/120)*100
where isnull(saleprice,0) > 0
and IsTaxable = 1
Don't forget to change your tax rates to 20% in the admin (Taxes -> edit countries) and once again, please test this on a safe database before trying it live.
Hope this helps, get in touch if you need any help. As you can imagine, we are pretty busy changing prices for clients in the UK.
Adam
Webopius.com