Okay, those of you interested, the SSL certificate error is happening on IE8, (Firefox, google chrome, Safari, opera all ok).

Theres no error on the home page anymore (ive removed the Site seal box and images), but now when you go and click on "login" it comes up with the error there. Nightmare.

Onto my Provider (HeartInternet who have resold the GeoTrust SSL as they dont provide the details so you can purchase direct from GeoTrust)

Will keep you all informed.