Sorry @jetxJust seen your comment.
I am thick!
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Thanks for this.
Using Prestashop 1.7.6.7 the correct file was in
/src/Adapter/Presenter/Cart/CartPresenter.php
For PS 1.7.6.7 a file named CartPresenter.php was in \src\Adapter\Cart but not the correct one.
Removing Tax inc/exc from the above worked great for checkout and also other places I could see the Tax Inc /Exc