VAT issue with Product Options

Currently using: 2.0.8

Hello, I’m having a slight issue regarding adding the correct VAT to products with more than one option.

For instance I have an item priced at £9.32 exc. VAT. There’s a product option for it (a length value) that adds £2.13 to the price, which works fine. However, when it comes to adding 17.5% VAT it only works it out based on the initial £9.32 instead of that + option price, meaning these items get undercharged.

I should note that for each applicable item, there’s an additional option select box for VAT Exemption. This is primarily for customers declaring a disability.

Is there a way around it that would save me having to add a duplicate item to the catalogue - one with VAT, and one VAT exempt?

Many thanks if you’re able to help.