Oh wonder that is the internet and online-auction-sites:
Went for it and got us a 'playworn' number 3 outfit from the mid fifties. Seeing this again, I think the old set we had must've been a number 1 set from the same period, remember it as a much smaller box. Also recall being a bit disappointed at the content; not even close to the promise of that giant crane on the front.
These boxes don't wear well, taped together at the corners. There is an instruction booklet for the outfit 3 dated (I think) as from 1954.
Used parts and almost a number 3 outfit as I now know. (No interest so niche that it doesn't have its online presence. Meccano is no exception, many very informative sites!) Missing are the two wheels (part no 187) and instead of these a large pulley (20a) and wheel (24) are in the box. To be fair, the seller did not claim for the set to be complete and made clear it had been re-strung with used parts. Also the small parts box is of course not original.
Being re-strung (with period cord) to an original stringing card, did not feel too bad about undoing every knot in sight and getting out all parts. To be played with!
Unpacking with a 7 year old: What 'instructions'? - wheels! First now to build a car. No wait, a crane :-)
With a length of the also supplied period-correct cord (40) and a bit of help. Apart from the two wheels, the set is nicely complete actually. A good supply of nuts and bolts (37), square nuts of course, clips (35) and even the cord attaching spring (176).
It's larger, heavier and feels generally different from the familiar Danish 'Technic' system. It also is a lot more fiddly and harder to get together. Prior experience in putting together Lego did not fully prepare the kids for the complexities of fiddling with Whitworth 5/32" threaded nuts. They're getting there...
And a simple garden seat from the instructions (model 0.3, by older sibling).
Did enjoy this. The kids enjoyed it. Enjoyed the kids enjoying it :-)
We'll see how this goes...