I found another brand of shellite today in Mountain Designs (outdoor shop) - Hateleys Shellite (a Hunters Products brand).  I'm thinking outdoor shops might be a good place to look due to shellite for use with camping stoves.

Incidentally, I tested it on a mirror with the Sceneys and Diggers brands again.  This time I made certain the mirror was absolutely spotless and streaked each out using some pieces of paper towel. 

All of them evapourated fast, and all three left ever-so-slight streaks behind, so I don't know if this is the paper towel or what.  The first time I tried it the Sceneys stuff was quite streaky but I couldn't replicate that tonight and I think it may have something to do with the dust on the mirror the first time around.

Smell wise, the Diggers definitely has the sweet naphtha smell, Sceneys is the harshest and Hateleys lies somewhere in between the two.