Fix GIF Image (Slow in Internet Explorer 8)

I had this GIF image created but can't get to the bottom of why it is slow in Internet Explorer 8, think it might do this on other versions too but this is what i'm testing it with.

http://www.on-holiday-claims.co.uk/images/offers.gif

Works fine in Chrome.

Think it may be due to the frames or something according to a quick search in google.

I have the original PSD so it won't need re-creating.

Thanks