Hi Ernest,
Thanks very much for that. I have put the new CSS in and the error messages have gone.
Regarding the other issue, I don’t know what was happening there. I was receiving a warning on page speed insights about the scripts that has now disappeared. I think it must have been to do with a change I made in Autoptimize. Anyway, as far as I can tell, all is OK. I’ll let you know if I receive another message in the future and will send you a link to it.
Thanks again for your help!