Thanks for the replies everyone. 

Gail, thank you for putting me right on the Set option, I had no idea all this time about it.  Chris, thanks for explaining it,

I will say my "Repointing blame" comment has been misunderstood - I had simply meant finding out where the problem lay, and explaining the same to management, and if it's not code, then it's unlikely there's anything we as DBA's can do (sans purchasing authority) to expedite a fix EXCEPT liaise with the relevant parties.  Naturally if just the code which has fallen off the wagon, and we hadn't flagged up those nasty 20 unindexed joins earlier, we should of course do the decent thing and own up.