[john tomkins]

Yes.  They weren't too dirty, had been cleaned trad in the past.  They must have used gg3 or something because they came up fine.  (I checked them all afterward)

As for flow rate, I always use setting one on the b/pack.

Nowt to do with luck! 

Did you manage to go inside every room to check all the windows afterwards, or get the ladder out and have a good look.
Not being funny but I wouldn't even entertain a first clean on setting 1 of my backpack, I can piddle twice as quick