I only now spotted this thread. I have a Workingmans 12 - I assume that it is an early one, as it has a 3-digit serial number.
I used it at church - 250 seat capacity, drum kit. Although we have a PA, and the SWR WM 12 has a DI out into that PA, most of the sound was from the stage.
It sounded a bit breathless and shouty because it was working hard to fill the room, and to manage the low B. However, the gig didn't demand lots of trouser-flapping bass - instead, it gave me the musicality and definition that I needed
It remains a great amp, which I still use for gigs. No plans to sell it on
And to think that I am only up the road from you - I am in Swanley, albeit 6 years too late. Sorry that I couldn't give you a demonstration when you were searching.