WordPress woocommerce plugin development finish existing project

Hi freelancers!
I’ve written some code for a wordpress plugin which asks the user to define which country they are in through a dropdown.

We save the 2 letter country ISO code into a $_SESSION variable, e.g ‘GB’ or ‘IN’ or ‘RU’.

What we want is for the woocommerce shopping experience to then calculate correct tax rate for the given country.

We have already written the plugin and it *should work* but there is a bug – sometimes woocommerce seems to remove the tax and sometimes it does not.

Unfortunately due to time pressures we’re unable to dedicate more time to debugging – but what we need:

– Someone with woocommerce experience ; the issue seems to be around private sessions/customers who have not yet created a basket
– An understanding of wordpress

Ideally: you will bring your own dev instance of wordpress + woocommerce so that we can see the solution working – you will receive the full source code to the existing plugin/project.
Alternatively you may be able to use our dev server.

Setup of a woocommerce store needs to be:
– Display products excluding tax
– Tax: GB: 20%, everywhere else: 0%
– Input product prices including tax
– Calculate tax based on shipping country/address

Demo product 1:
– Price: £10.00
– Tax class: Standard

Demo product 2:
– Price: £20.00
– Tax class: Standard

When a guest user / visitor selects:
– GB, they should see Demo product 1: £10.00 (8.33 exc VAT)
– US, they should see Demo product 1: £8.33

Presently the functionality seems to be intermittent and vary between browsing sessions – could be a session issue, or could be related to woocommerce and the way we’ve setup the cart session.

Thanks for your consideration.