Yeah, I tried that already and it didn't help. Presumably the code that generates the price using this function specifies the precision? Is there any reason why this can't be changed to be the same presision as the code that generates the prices that are displayed and where would this be done?

Alternatively simply multiplying the displayed price (which is rounded to 2 decimal places) would seem like a good plan no?

Regarding the reasons why I am usng a currency multiplier whilst residing in the UK. I am not charging tax currently although I perceived that I might be and so I inputted all my prices as net of what the vat would be, set tax at 0% and currency to the current vat rate is (for some reason, and I can't remember why, this came out at a strange number of 1.4999...). I figured If I neded to charge vat I would simply create a vat rate and change the currency rate back to 1 and hey presto (all the products have tax classes set where appropriate to make this work).

I know I could have written a script to amend the the prices in the db but this would have taken longer