AMA Tiling
TF
Is that adhesive ready mixed or powdered? Not one I'm familiar with.
Powdered I guess. Larsen very common in Ireland. Some of its ok I suppose but not really an adhesive of choice. Cheap I gather with practically every hardware store and tile shop having stocked it at one time. Looks like a lot of work I come across. Well enough set out, spaced and levelled etc but what lies beneath is dubious. I could be wrong but it is fairly common. Old case of people think it looks great then it's well done. I wouldn't rule out the tiles but judging by the pattern of the shadows it's more than likely the adhesive.