If you check the rest of the forum you'll see that Massive Events (Showmasters' sister company) is running The Hub which is a Torchwood convention. Showmasters had Torchwood guests before too. John Barrowman has attended both SM shows and ME shows in the last years. So they probably know he's available.
Yeah i know JB did CMK 2008 too .Just in case they were not aware that the TW cast except Burn Gorman all seem to be around at the moment,Would love to see them all at CMK Again as it is my fave and the only one that me and my family attend