Hi there everybody
I don't know if this is documented but is worth pointing out, as Mark Lee from Stack Ideas has identified for me, that if you use the Invisible Recaptcha feature but you do not set the API Keys correcly, then submitting the form will probably break ( submit button sits in a spiralling icon state and your comment will not be sent).
To overcome this, Invisible Recaptcha was disabled and the standard V2 Recaptcha was implemented instead and all was well.
I'd like to thank Mark Lee at Stack Ideas for his prompt support on this one.
best wishes
Chris