Epi, is your persistence on this topic intended to imply that Mark Ravenhill did indeed co-write it but then insisted on being uncredited? Do you have evidence? Or is it just a hypothesis? Or are you just being mischievous (as usual)?
Out of interest this week's Stage has a vicious "Vicious" review from Harry Venning which states at one point (having refered to the cast presumably having taken part due having close relatives held to hostage) "The same applies to highly respected playwright Mark Ravenhill and former Will & Grace writer Gary Janetti who provided the scripts .... ".
Inexpicably he liked The Job Lot.