Not actually tried new batteries yet as I can't find the right size
However I contacted the seller all of 2hrs ago and man was I impressed with the response.
Wasn't even expecting a reply, supposidly its one of two problems 1) faulty batteries(shouldn't be allready wasted) 2) something is loose in the back and it should be an easy soldering job... He said I could send it back to him and he'd solder it for me, v. nice of him.
Once I unscrewed the back the noise stopped but if you put any preasure on it the noise starts agin so I reckon its problem 2. Will give it a try anyway.
col