Reducing alarm sensitivity

[bignips]

This has been talked about way back, but like others my Sagaris alarm tends to go off when people walk past it,especially at the back!
I found the sensitivity adjustment box (by handbrake--a bit fiddly!), but, if you look at the picture, shouldn't there be a twisty nob to adjust it?-I looked into the little hole with a torch and couldn't see a screwdriver slit to use.

Edited by bignips on Monday 9th April 19:42

[bignips]

Forgot the picture!
Here it is,

http://i148.photobucket.com/albums/s3

Edited by bignips on Monday 9th April 19:43