beat wrote: Any standard CB text field can have server-side validation using a regex string. Just add such a field with your question as title and your reply (or set of possible replies in a regex server-side validation.

Thanks for this suggestion, Beat. I've implemented this now, so hopefully that will deter the spammers without deterring our target audience.

Best regards

Shane

Just in case anyone is interested, this simple fix was very successful. I added a field to ask users to enter the postcode of the school. Postal codes here in Dublin are numeric. I included the answer in the field name like this;

"Postal district of school (Hint: answer is 16)"

This has completely stopped all the spam registrations, but doesn't seem to have been a problem for real users.