TOPIC: IE doesn't allow registration

When trying to make a registration using old DT (3.0.9a) and new DT (3.1.1) when using the latest version of IE (11.0.XX) the process reverts the user to the events listing page. To the user it doesn't appear to error out, simply IE doesn't allow the user to go past the Events listing page. So by clicking the registration button for a particular event, it just keeps the user on the events listing page.

However, if I select Internet Options and Delete Browsing history, for a few moments the system WILL allow clients to select registration and complete a registration process. But go back into making another registration and its blocked again.

I have no such problems with Chrome or Firefox on Windows, OR Safari on any iOS device.

But I do get clients saying "your booking system doesn't work!" when using IE - so it's not just my computer/software.

So I've had to put a warning on my site saying DO NOT USE IE which although isn't a great browser (and no longer all that popular) looks very unprofessional.

I have Sh404SEF working and thought this might be causing it. However after completing disabled this, refreshed everything, no difference.

I have logged a support request with DT Register over a week ago but no reply or help.

Can anyone help? Thanks