This appears to be a non climbing form of Fortunes double yellow. The flowers are larger and less full. A rose of this description is also mentioned in Gwen Fagan's book 'Roses at the Cape of Good Hope'
That's correct Pat, I've found this rose several times around here, (S.W. France) and not much info other than its very old and it had been used in the vineyards to detect oidium
We've made "Mill River Farm" a synonym of "Tordun Hybrid Gigantea". If anybody notes any differences, they are easily separated. Gwen Fagan's reference has also been added.