Not working in IE? Hello?

Thats unfortunate.
Which of IE are you talking about?

https://wicky.nillia.ms/headroom.js/
Here you can find all the info you need most likely.

If you tell me the version number I will check myself and will fix it for you.

Thanks for getting back to me. I have created a temporary test site:
https://speedypancake.co.uk/dev/headroom/

The header disappears when scrolling down as desired in FF & chrome, but just stays put in internet explorer (v 9)

Thanks