Sorry, Oliver. I had forgotten that you had the SR15's. I don't know how I would, since they've come up in many a discussion. I've had the Wright's mated with a pair of 90dB speakers, and it worked, though not nearly as well as with our 104dB horns.
The comparison I was speaking of involving the Wright's was conducted by 5 or 6 reviewers for audio publications, and it was their consensus that the Wrights sounded the most "right". Personally--and I'm sure that I am forgetting some--I've heard the deHavilland SET's, two or three Audio Note examples, of course the Audion (which we still own), several DIY's, Decware, and several others. As has been mentioned here, his 2A3 SET's don't have a big bass presence. We are using them with a powered sub, so we don't lack for bass. Certainly, they don't do everything, but honesty is their forte.
With your Silverline's, an Audion Sterling MKII would be an outstanding match. It's a one-source, 12W EL34 'integrated' (with volume attenuator) that turns ultralinear at a specific volume. You get outstanding SET midrange, as well as tight, punchy bass. They were $2100 retail, so a used/demo example would likely be right in your price range. The MKII is far better than the standard version, in my opinion.
I hope you are doing well, and enjoy the show you are attending in England.
Howard