Hi David,
No, I’m afraid no one has responded in the Google reCAPTCHA sub-forum either. I have just disabled comments entirely on my site to prevent further comment spamming. It’s a shame to have to do that for now, but hopefully someone will offer some help soon!
Thank you, Tara!
I have also posted my inquiry in the Google reCAPTCHA sub-forum as suggested. I will leave this here for a few days just in case.