HelpMeFind has just two choices:
1. armed with thorns / prickles
2. thornless (or almost)
(for which I am a little pleased actually, as I have rose bushes here which on occasions can have four prickly canes, and one utterly smooth cane.)

The source link (David Austin website) says of 'Carolyn Knight': apart from colour, all other characteristics are the same as 'Summer Song' from which it sported.

The U.S. patent for 'Summer Song' says:
Prickles: Quantity.--On main canes from base: Ordinary, 4 per 10 cm stem length. On laterals from main canes: Ordinary, 5 per 10 cm per stem length. Form.--Concave curved inward. Length.--9 mm. Color when young.--Greyed-Purple Group 185A with Yellow-Green Group 146D at tip. Color when mature.--Greyed-Orange Group 164A at base, Greyed-Purple Group 184B at tip and along upper edge. Small prickles: Quantity.--On main stalks: None. On laterals: None.

If you can work out from that what we should list, we would be delighted to correct things.
You might like to see some homework I did to teach me about prickles years ago:

PRICKLES (prickles, bristles and glands)
Thorns spring from the wood. Stiff and immovable. A Bougainvillea has thorns
Prickles grow from the bark and can be easily rubbed off. Roses have prickles. Stiff and immovable.
Bristles can be moved as the hairs in a brush

Prickle Colour Immature _______ Mature _______ Old ________
____________ red, brown, grey, white, black

Prickle Duration
Caducous when they fall with or after the leaves and don’t stay on the wood long than 2 years.
Persistent when they become entirely woody, very hard and stay several years on the old wood.

Prickles - Where and number
Thornless; Almost thornless; Few thorns; Prickly;
Sparse (placed without order here and there); Grouped (several close together at certain places, while lacking in other place); Close-set; Dispersed; Scattered; Bristles (gallica); Intermingled with bristles (centifolia); Single; In pairs; Geminate (placed in pairs); Often paired; Infrastipular or stipulary (just below the base of a leaf or stipule)

Prickle - Shape
Simple; Compound (as in R. simplicifolia (Hulthemia persica); Alike - (all straight or all hooked);
Dissimilar (some straight, others hooked); Sharp spines; Thin sharp; Needle-shaped; Curved; Large curved (tea, bourbon); Slightly curved; In an Arc; Hooked; Very hooked; Falcate (hooked like a sickle); Straight; Nearly straight (alba) ; Flattened; Thin; Slender; Thick; Wide; Broad at base; Narrow at base; Width variable; Dilated at the base; Base enlarged; Base thick; Base compressed; Base decurrent (prolonged stemwards); Winged thorns; Wing-shaped; Thorny; Strong; Fierce; Weak (easily pushed off - gallica); Short; Long; Equal; Unequal;
Prickle - Size____________

Bristles
Colour ______________;
Bristles can be moved as the hairs in a brush. Bristles; Rare; Sparse; Grouped; Numerous; Innumerable; Close-set; Stiff; Soft; Equal; Unequal; glandulose (topped by a gland; Stiff glandular hairs; Aciculi (needles); Setiform - thorns degenerated into bristles.

Glands
Colour ______; Sessile (no stalk); Pedicellate (stalk) ; Spherical; Oval; Disformed (irregular form);
Fragrant; Scentless; viscous.

And this is exactly why comments like yours are so useful and what makes HMF so special. At some point in time, a permanent reference indicated otherwise and now we know that reference is in question based on your experience.

We need more people take the time to share their experience - Thanks !

I took a piece of FEL with me a few years ago when I was going to San Juan Bautista. I held my piece against the plant there and couldn't find any difference. I'm pretty sure all the old climbers in that part of the park came from Roses of Yesterday, with the clincher being that the rose they had labeled a multiflora turned out to be Laure Davoust, which Francis Lester had found and sold under the name Marjorie Lester.