Some picture's of crook core plugs follow.

Darren's Weeping Welsh PlugThis is what you can expect to see if yours starts to weep.

Lawence's Welsh Plug - inside view (central hole used for removal)

The cylinder head core plug from a Ducati 748/916/996/998/ST2 and ST4 will fit the Benelli Tornado and costs about 70p. In Australia it will cost about $5.00. If you spin the right story, Ducati will give it to you for nicks!
Ducati Part Number 87310011A

Actually, as Baz (in Jindy) found out, the core plug is a standard 16mm brass type, available at just about any automotive store. Baz picked his up from Repco (remember the Repco Brabham?) for $1.