You picked venues that see a lot of action, never fished the Royalty despite living nearby in the late 70's and 80's, actually lived right by Throop, but alas work etc was the main focus.
The list changes, a few years ago it would be the Hants Avon first
The Wye now
Severn...Grueller on the Lower, but the potential for an occasional big Barbel
Warks Avon, been very good to me, just last week had two over 13lb.
Teme (holding out for this one), wild river a Barbel fishers dream, sadly not so anymore, but there are improvements to habitat that might help.
Bristol Avon (my home river, and perhaps the most beguiling of all, some long stretches that see little action. My first Barbel from here, and was my go to River as a kid, you know the drill, rod strapped to the crossbar and haversack.
But many many more, but that's the five....
Oh! well done on you lump from the mighty Trent, never fished the Trent, but would love too. (6?)