If anyone is having trouble with this – I resolved the problem by changing (like the error says) the call cart->tax_display_cart in line:
if ( wc_tax_enabled() && ‘excl’ === WC()->cart->tax_display_cart ) :
to cart->get_tax_display_cart
In my case, using estore theme, this was line 82 in file …\wp-content\themes\estore\woocommerce\cart\cart-totals.php
