Hi Doun,
I've just seen your post and the replies.
Previously on Rootschat, reference was made to a Google application that tied together detailed topographical maps and corresponding vertical aerial photographs. If you Google "wheresthepath" it will refer you to this site. Once on it, type in "Douchlage" as your search term, and the current OS map for the Drymen area will be shown with a moveable cursor centred on the farm. Adjacent to this will be the aerial photo which matches the map area shown, the photo has a moveable cursor linked to the one on the map. Maps and photographs are in scale, and either can be dragged as required.
Hopefully this can supplement information you may already have, or that has been offered.
Regards,
Istrice