'Spaw, I've definitely got a cousin of your moggies here in London. It's a dedicated and impressive pisser - albeit a pisser with discernment.
Trouble is, it won't do the business with audio or video casettes; this little bugger has a passion for pissing on linen bedsheets!
As for the cassette problem - I solved mine yonks ago by divorcing. It's amazing how custody battles can resolve some things... Now I'm CD and MiniDisc only (with the best of the old cassettes backed up to MiniDisc).