IE11 issues with site not working properly asp .Net 2.0

Hi - any help would be greatly appreciated.

Basically we have reports generated and displayed in browser using sharepoint 2007 and excel rendering.

When using IE 11 the reports generate but some of the functionality does not work such as drop down arrows in cells.

Setting the site to compatibility mode solves the issue, but we want cant do this for the users.

I am looking for something to force IE11 to se the web agent string to IE10 which seems to work.

Reading online I have found out that you can have a .browser file in the app_browsers directory which can be made to force IE11 to IE10 compatibility mode.

Basically this explains the work around I am trying to impilement:
http://blogs.telerik.com/aspnet-ajax/posts/13-12-19/how-to-get-your-asp.net-application-working-in-ie11

Except I am using .Net 2.0 - should this still work?

I have tried restarting the apppool after making the changes and deleting files from the temporary asp folder but when I press F12 in IE11 the user agent string is still 'Default'.

Any ideas what could be wrong?
(I do not have the option of updating to .Net 4/4.5)