ID for rose foundlings is rather problematical, sort of plant history, botanical obseration and a pig-in-a-poke guess.
From what you say and by the look of the flowers, leaves, bark, thorns and heps I'd hazzard a remontant 19thC plant with breeding across one of the Chinese reblooming evergreen roses and a Centifolia, less likely a Gallica. That would come down to a Hybrid China, Hybrid Perpetual or a Bourbon rose. My feeling is the shape of the flower and the number of petals rules out the HP option. Now the problem becomes one of how does the plant grow in reasonable garden conditions; not Cretan churchyard conditions. If the growth is tall, willowy, somewhat lax-ish I'd plump for a Bourbon; if bushy and relatively shrub-like I'd suggest a Hybrid China. Any chance of having observed it under good conditions in a garden where it is cared for, watered, pruned, fed etc? I will keep thinking and looking over the holiday season.