Since you are in the UK I would listen to UK made speakers. The best of UK speakers are unknown to almost all of the forum members here. Their recommendations are seriously inferior to the manufacturers I listed. You can forget DefTech. Their speakers are uniformly in the dreadful category.
I would seriously go and listen to Spendor. Spendor is one of those companies founded by BBC engineers. Every speaker of theirs I have heard is always beautifully balanced. If I had to give up my speakers, and wanted the best value for money then Spendor would be top of the list. Of all commercial speakers the type of sound stage and their presentation is probably more akin to my designs than pretty much any other manufacturer.
There is a brick and mortar store in the Twin Cities that has been a Spendor dealer for years, and the line has been a good steady seller for them. The market hear in the Twin Cities is in many ways more akin to the UK market than other US markets. The reason being that we have tremendous musical activity here, with two full time professional orchestras, a host of good choirs, two of them fully professional and an abundance of good amateur choirs. We have a professional opera company and baroque ensembles. There are also highly competent performing groups all around the state. You would have to go to New York to find more activity.
For the type of program you listed for your preferences, then only superior speakers will fit the bill.
The classical market is much bigger proportionally in the UK than the US. In fact it is probably dominant actually. So speakers have to be good. It is hard to sell bad speakers in the UK, let alone manufacture them. Selling lousy speakers in the US seems dead easy.
You can audition Spendor and Harbeth speakers at Radlett Audio in Saffron Walden Essex. That will be a little trip on the M25 to the M11 for you. You are close to the M25 inside the "beltway".
I know the Herfordshire, Essex area pretty well. Our North London heavy equipment yard was on Cheshunt high street. The South yard was at Greenhithe Kent. I grew up in the Medway Towns.