digdug123: I'm sorry to say that after spending several hours working on 'Knock Knock' (without success), I have decided to archive it [:(]
Due to water ingress it would have needed a complete overhaul, and as the cache location has been sold it wouldn't have been available for much longer anyway.
As I knew this day would come I took the precaution of making a video of the container in action.
For those interested it can be found here,
http://youtu.be/KmKShCpmLW8
I apologies to those of you out there that wanted to bag this one, but unfortunately will no longer be able to.
Kindest Regards and Happy Hunting, Digdug123 aka Steve.