Site Builder Tags in Suitescript

I'm currently having to add links throughout our sites to comply with the new GDPR regulations, which I'm doing using site tags (ie. Setup > Site Builder > Tags).

I've managed to do this on most of our forms by including the tag in the main page HTML and moving its output over the form iframe with CSS positioning. I am however having an issue with an email signup form which loads a form in an iframe within a pop-up lightbox modal window. I've tried using the tag within the form HTML template, but this doesn't work.

Can anyone advise if there's some way to include the tag in the form template HTML - and, if not, is there a way to access custom tags within Suitescript? If I can do the latter, I can inject the value using ajax and either an SSP handler or a suitelet.