Otter, I think they own the original copyright as they are the publishers of the original magazines the drawings were originally published in. There could be a bit of a dispute between the draughtsman and the publishers for him not getting a cut for this extra selling of his plans but I presume he may have given up all rights to the plans in the contract (if there was one?) when originally published?
Ugo, I can't comment on the ES2000 perhaps you could email them but I will scan in one of my plans later and post up for you guys to check out.
I presume that over time many different draughtsman have created these plans for the magazines in question so I suppose what with there being no preview, it's a bit of a lucky dip in regards to quality. A photocopy is a photocopy. It's what's on it that matters. You might get lucky. I mean I'm only interested in the Luftwaffe plans and I did not have any good He59 or He115 drawings and plan on profiling these later for a project I'm working on but are there any rare plans on the list?
Regards
Clint