Thanks for your reply.
Yep I was using the recaptchav2 extra too.
Added recaptchav2 as a prehook to the form, added the following in a chunk:
And called that chunk in the custom field.
Now, the Recaptcha field would show in the form and was operational, but regardless of whether it was completed or not, the form failed to submit.
No validation errors appeared.
This was true with the field required and not required.
What am I missing?
Ta again for any help.