Excellent James, thankyou. Exactly what i needed to know that this is common. Will just leave it and monitor how it goes.

I haven't read the whole thread but I really wouldn't worry about it. My engine was taken out of a disco and had the defender air filter bracket attached to it. I removed the two bolts and torqued htem up as per spec. That was back in April 2003. 12 years and 100,000 miles later, all's still ok.