How can I run/emulate IE 7 to access a site that only works for IE7

Have you tried this product here.

http://techie-buzz.com/tips-and-tricks/how-to-run-ie8-beta-ie7-and-ie6-on-the-same-pc.html

There is a developer tools section in IE8, Tools -> Developer Tools (or hit F12).
If you hit that, it will then open a window, on the tool bar there it asks for browser mode. Select IE7 and you are there.

Another option is to use VMWare to run multiple versions of Windows on your desktop - which gives the additional benefit of being able to test on a completely clean and new installation of Windows.  On the down side you do need to purchase multiple copies of Windows.  If you want to go that route then consider purchasing a copy of the Microsoft Developers Network (MSDN) Operating Systems version which would give you access to multiple versions of the Windoze operating systems.

Thanks ...
I can't go down the vmware route but thanks.
Will try the internet exlorer connection in due course.
Have looked at F12 option, I have selected IE7 - what do I do next - I tried the search bar, where you can ee the URL with both http://vebus. defra. gov. uk and vebus. defra. gov. uk options. I tried going back to IE and going to the site and get the same message about IE 7.
See attached...
ie7and8-01.jpg
ie7and8-02.jpg

simonrobs--Run IE8 in Compatibility View
http://msdn.microsoft.com/en-us/library/dd567845(VS.85).aspx

The only thing that definitely worked - thanks