Hi Antony, really appreciate you respecting the no links policy - especially as the whole point is to change the sample page as soon as possible to get it working ;) We also try to avoid taking conversations off-forum so we can make sure the solution remains in the thread and helps anyone else with the same problem in the future, but enough admin - back to code :)
Using your provided code works for me in ff, Op11, winsafari4, so the issue is your ie. So:
Have you checked you have ie9 standards mode rather than an older compatibility view?
I can't test, but I ust realised the doctype in your provided code is: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> That switches ie into non-standard mode. It's not really best practise to use it for coding so try your test page with the following (full) doctype to try the page in standards mode: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
As already suggested, make sure you send the type in your link to the style sheet, so change <link rel="stylesheet" href="testmystyle.css"> to <link rel="stylesheet" type="text/css" href="testmystyle.css">