Sorry, I wrote in my previous reply "I just checked my widgets and each of them appear to have an unclosed div."
I should have written "I just checked my widgets and each of them appear to have a closed div."
I have done as suggested and moved each widget across to 'inactive' and finally discovered which was causing the problem. It's the bottom one, but, it seems fine, though it does have a long complicated looking code.
When I cross-checked with http://validator.w3.org/check?uri=http%3A%2F%2Fwww.creditrebuild.co.uk%2F&charset=%28detect+automatically%29&doctype=Inline&group=0 it showed the following against that widget:
Error Line 409, Column 124: An img element must have an alt attribute, except under certain conditions. For details, consult guidance on providing text alternatives for images.
…://www.halifax.co.uk'><img src='http://test.mecseo.com//halifaxlogo.png' />
It indicated that the > was missing from png' />, but, as you can see below from my actual code, it isn't missing.
<img src='http://test.mecseo.com//halifaxlogo.png' /> <div class='tamco_code_holder'>
So, still not a lot further on, apart from the fact I've now identified the widget that's causing the trouble.