After the effort to get reCAPTCHA to work we still got spam and from the context, frequency and no. of pages viewed they were bots.
To fix I made a small PHP script to send the contents of the message to my email address at work, after which I will manually add comments after reviewing them first. It seems the only way to fully block all spam.
Google has now reduced our website to 2 extra links under our main URL due to this latest spam, so I can't take the risk any more. I HATE spammers
By the way if anyone wants my code for the message system, pm me and I will help you implement it, maybe you will have better luck than I did!