There is a bug with your theme development, or the developer that edited it, forgot to change the query string.
Currently, you would need to exclude all files under your theme directory by adding /themes/yolanddesign/
to the css and js ignore list, however, the real reason why this happens, is that your theme css and js files change the query string on every pageview.
For example:
https://bramleyappledesign.co.uk/wp-content/themes/yolanddesign/fw/js/swiper/swiper.css?rnd=2142481582
The ?rnd=2142481582
changes on every time you refresh the page, and this is wrong.
Tell your developer to remove the rnd
query from the enqueued assets, so that they can remain static and not change on every pageview (do not install another plugin to remove the query strings… they guy added it with code, so he needs to edit it again, or ask the theme author).