OK, I'm back home! We have three photographs of men with musical instruments.
Scan 1 - the man on the left is holding a guitar with what looks like a very high action which means it has been set up to play with a steel - i.e. Hawaiian style. The one in the middle is playing an electric lap steel, as I've previously said, and the one on the right an ordinary electrified acoustic guitar. It looks like a Gibson ES 150 - said to be "one of the world's first significant commercially produces electric guitars" but, unfortunately it isn't - the head is the wrong shape. The ES150 was first produced in 1936 so I would speculate that the guitar in the photo must be from the late 1930s at the earliest.
Scan 2 - The same man on the left is now playing a Ukulele (Hawaiian for "jumping flea"!). These come in various sizes and I can't tell whether it's a Concert or a Tenor. As I've said previously, the man in the middle is playing a Dobro (an amalgam of Dopyera Brothers). These were produced in that particular style from around 1929 but, unfortunately, you could just as easily go out and buy one today which looks identical. There were differences by which they can be dated but you'd have to have the thing in your hands in order to tell. The one puzzling thing is that it has a "trapeze" tailpiece which I thought might have given a clue as to its date - they don't have them like that nowadays - but I can find no reference to them ever having had one like that. It's possible that someone changed it at some stage. The man on the right is playing a different electrified acoustic guitar - look at the end of the fretboard - it's a different shape.
Scan 3 - We now have 4 men. The two at the back are playing nondescript, un-identifiable guitars. Both men at the front are playing Dobros. Quite what the cone is, on the floor at the front I've no idea. Their clothing seems to come from the 1940's
One further thing that is puzzling me is how did two chaps from Sheffield end up owning 2 Dobros? They weren't exactly common-place back in the 1940s. I remember Tommy Steele once saying that his ambition, when he started out, was to own a Martin guitar (similar quality to a Dobro) and they didn't start importing those itnto the UK on a regular basis 'til the 1970s when I first bought one.
If anything else strikes me I'll get back to you.
R