Sorry I can't show you a photograph, but yesterday in the well-kept
but still otherwise flowerless rose garden at Warwick Castle I saw a
medium-tall rose in full flower rambling through some sort of cherry
tree. It had clusters of one-inch-wide scentless fully double rosette
blooms in a deep cream shade. The small foliage was of a fresh green
colour; and the plant was completely thornless. A passing gardener
didn't know what it was.

A variety of R. banksiae, perhaps? Is R.banksiae thornless, or does it
come in thornless varieties? Or what?

(The said gardener was chatty, and recounted how when one visitor had
asked him for a cutting of something, he'd replied "Of course, madam!
Shall we use the secateurs you've got in your bag?" I truthfully swore
I didn't have so much as a Swiss Army knife about me, but my daughter
rather let the side down by saying "That's not like him!")

--
Mike.