Making Captcha Field "Required"

I have set up a form along with a captcha field

All ok, unless someone forgets to put the code into the captcha field.
What happens then, is the page is reloaded (blank form) without any hint of anything being wrong.
Therefore the user may assume that the email with their question has been sent, when in fact it hasn't (which is correct!).

Is there a way I can make Chronoform check to see whether the captcha is empty on submission and present a reminder message to fill in the code?

All other required fields work a treat.
Form is here : http://shinetogether.org.uk/General/contact-form.html

Many thanks
Peter

Hi Peter,

ChronoForms does show a message but something on your site - the SEF URLs I think is redirecting the page I think. It behaves correctly if you go here without the template.

Bob

Captcha is sensitive. Sometimes we have to refresh it when we find it difficult to read.

Hi Bob

Well that's good news .... in a way!
Now I need to find out what is causing the issue, which is a little beyond my expertise.
If it helps I use the latest version (downloaded and installed earlier today)of sh404sef

Initially after I looked at your posting I thought I had forgot to put the message placement code into the template, but the Chronoform error message doesn't use that as far as I can tell.

Any ideas/pointers would be gratefully received.

Many Thanks
Peter

UPDATE :

I have now worked out how to make this work correctly.
By using the module mod_chronocontact and then placing the form on the article by using {loadposition} I now get the error message as expected.