I was sitting in the Red Rooster drive threw waiting for my large Flava combo then the fan started up and the car acted as if i turned on the aircon. It was going on and off in bursts and each time, the car would drop revs.

Never noticed it in my other 1st gen.

So is this normal ?

By how many revs does it drop? I think mine used to move maybe 25-50 rpm, wasn't huge, but noticeable.

I would say about 200 to 500 rpm.

Your Idle Speed Control motor (ISC) should be keeping your idle speed in check. It sounds like yours is playing up which is not an uncommon problem. I'd suggest hunting down a copy of a service manual and running through the checks for your ISC. I'm not sure if the 1st Gen manual is available for download somewhere??

Nah i dont think it is, but Ol Fart might be able to scan me the relevant pages from the manual :)

I don't know if this would also be a cause of a stuffed ISC, but i have noticed the engine cannot keep a steady rpm at idle and if im driving and throw the clutch in, it drops to about 200rpm then bounces back.

If it bounces back, then that to me would indicate that the ISC is working.