Using either Windows 7 / IE11 or Windows 7 / Chrome - neither form allows entry of the 4 digit “bot” code.
This is probably because whoever set up the form didn’t test those operating system / browser combinations as they're quite old, but there’s still millions of us using Windows 7 (I'll be dragged kicking and screaming to Windows 10)!
Please, please could you pass this on to your tech team and get them to have a look - it wouldn't take much to correct it. Thanks