I think that the ball is now on Andrew. As I said, the error is coming from Apache and looking at Apache error logs would tell us more about the issue.
Im so sorry i thought i had responded to this thread saying the server had fixed the issue. It was down to some cache or other which I thought I had already flushed but I guess not. Maybe I responded without having logged in or something I don't know.
Anyway, the issue is now resolved thank you all so much I looked to see if there was a way i could mark it as such but can't see anywhere to do so.