Always Force non-AMP version of a particular page

This page https://the5krunner.com/subscribe/?noamp=available
has a SUBSCRIBE button inserted from a shortcode from the Paid MemberShips Plugin
The JS behind that button doesn’t correctly run and ‘hangs’ saying ‘Processing’

their support team has simply said to me that their plugin is not compatible with STANDARD mode for the AMP plugin.

If I run my site in TRANSITIONAL mode it all seems to work fine and the non-AMP version of the page is used.

I want to use STANDARD AMP mode as TRANSITIONAL mode causes a whole host of MANY other problems for me (eg responsive content)

I thought I would force the display of the page as /?noamp=available

but that does not seem to work.

Any suggestions as to what else I can try or am I forced to use TRANSITIONAL

ty

The page I need help with: [log in to see the link]