Once again thank you for your help.
Would you be able to provide me with details on how to implement that solution, as it is beyond my current knowledge of wordpress.
I assume it goes into functions.php but I don’t know how to write any additional code for the solution you provided.
thanks
Issue now resolved, the problem was caused by a plugin conflict with WP Image Carousel. Once this plugin was deactivated the dropdown lists populated correctly.
Thanks for the reply. I have looked at the guide and while I was able to modify the colors on the single event page I am still unable to set a condition to allocate a color depending on the category.