Use a variable price value for schema on product.tpl

[Guy @ GCL]

So I have a PS v1.6.1.17 installation which I have a recurring problem with Google banning variable products because the schema.org price is not updating when the product combination is changed. 

When the product combination is changed, the schema value for price is not changing as it is being passed through the variable $productPrice which is static doesn't change from the default combination.

I want the value of this to reflect the price of the currently selected combination.

e.g. for the default combination this would produce a value of 1.11 in the content 

<meta itemprop="price" content="{$productPrice}" />

But when I change to the next combination (product price 9.99) this value does not change and stays at 1.11

When I change this {$productPrice} variable to something else like {$priceDisplay} it changes the html to this:

<meta itemprop="price" content />

I can't seem change this to the price of the currently selected combination. HELP!

Edited January 30, 2019 by Guy @ GCL (see edit history)