Broken drop down menu - Mobile

Hi All

I have a page with custom calculator on it. I paid a friend of friend to build it for me but now has stopped responding. The calculator works but when I insert it into the page it breaks the drop down menu. (only on smaller break points). See screen shot. I’m thinking it must be a conflict with the bootstrap css but can’t figure it out. Anyone got any ideas.

Thanks

Jason

https://eurotank-2018.webflow.io/truezerocopy

https://preview.webflow.com/preview/eurotank-2018?utm_source=eurotank-2018&preview=af817025725c4837f82f8b8034143c8c