Plugin Slows Down site

I really like the Fitsoft plugin but it’s massively slowed my site down. I’ve udpated everything, upgraded to PHP 7.1 and tested with other plugins deactivated but I can see that, for some reason, the Fitsoft part takes a really long time to load.

Eg. tests with Fitsoft show page load time at 34+ seconds. Without it’s around 8 – 9 seconds.

Any ideas what I can do to fix this? I’d really like to keep using it as it’s perfect for my needs.

Thanks

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