This too had its first flowers yesterday morning. If it's indeed this rose--I just found it in our garden. (Maybe it was originally a rootstock.) But it's consistent with the description and the other photos.
We were away over the weekend, but one of the past three days or so Stanwell opened a whole bunch of flowers, making it the fifth rose in the garden, and the first repeating, to blossom this year. R. hugonis too has opened its first two flowers; unfortunately, they're somewhat hidden under the foliage very close to the ground.