As mentioned in the member's forum, I've visited the small Welsh village of Pontllyfni where the Pontlyfni meteorite fell in April 1931. The meteorite gets its name from the village near to the spot where it fell, but due to a mistake, the second "L" got missed from the meteorites name. The village gets its name from the bridge over the River Llyfni. I'd like to tell you that this is a picture of that bridge, but it isn't. This is the very picturesque Pont y Cim which crosses the same river just a few hundred metres to the east of the village. According to the plaque it was built for £20 in 1612.
The recommended coordinates of the Pontlyfni Meteorite fall are 53° 2' 11"N, 4° 19' 10"W. This confused me slightly, as the meteorite is reported to have fallen "within 50 yards of the farmhouse", but there is no existing farmhouse within 50 yards of that location. Neither could I find "Coch-y-Bug" (see here and here), nor "Coch y Bîg" on the Ordnance Survey map (OS Explorer 13 Lleyn Peninsula East 1:25000 scale).
After a very pleasant morning wandering about in the wrong area, looking for a candidate property, I explored a couple of very overgrown footpaths close to the recommended coordinates. I eventually found a public footpath along a well maintained track to 53° 2' 14.7"N, 4° 19' 16.5"W. At this location stood what is now a rather dilapidated building.
Looking at the door frame, I think it is a match for that included in the photograph of John Lloyd Jones holding the Pontlyfni meteorite - see here.
The adjacent land is pretty boggy and overgrown, but the best maintained footpath past the property is part of the North Wales Pilgrim's Way. I'll mention this to the person who maintaines the North Wales Pilgrim's Way web site and see if they're interested in giving a meteorite a mention.... [Updated] I have been advised that The Pilgrim's Way no longer follows a route past the site - explaining why the paths look seldom used.
Many thanks to the authors of the various web pages that are referenced here.