Calendar appearing all stretched out

I have just downloaded and installed the Pinpoint Booking System and set up mu calendar with certain hours available for selection etc.

I managed to do all that, but when I then add the shortcode to display the calendar on the relevant page, it appears all stretched out and strange.

The page I have it on is:

https://careondemand.co.uk/sample-page/

Would someone be able to point me in the right direction to be able to fix this and have the calendar display properly. I am looking to buy the PRO version imminently as soon as I verify that the plugin satisfies all my needs.

Many thanks.