Hi Phil,
Has the Diana 52 idea gone out of the window?
I have had mine for 10 years, so it probably needs looking at. The local gun shop will not touch it as they say "We only service proper fire arms here", so that leaves me and my tool box !!.
Also, as suggested before, looking at tools - but also home made tools eg how to make the tool used for cleaning inside the cylinder, a length of dowl and some wet and dry. This was in AGW some years ago but i cant remember how it was made.