Tannoy has made many different models of speakers over the years, and it's hard to lump them all together. The different versions of their dual concentric driver have similar, if not identical, sound and imaging characteristics.
I have owned three pair of Tannoy speakers over the years, and still have a pair of original Stirlings that I use in my den. They have a very unique sound that is hard to describe. You have to hear them, in your room and with your gear in order to decide if they are for you. I love them for jazz, acoustic instruments and especially female vocals. I would describe their qualities as warm, lush, fairly (but not overly) detailed and very musical. The imaging from the point source drivers is second to none, IMO. But if you are looking for big bass, super detail or high SPL you should look elsewhere.
Tannoy says that the larger models and the Prestige line need 30W - 60W power, and tubes are generally considered to be the way to go. Not to argue with conventional wisdom, but in my room my Stirlings sound better and have much better bass control with a current (or high current) SS amp, coupled with a good tube preamp.
Regarding the Tannoy DC10A - I haven't heard them. Frankly, I wouldn't spend $22K+ on a Chinese-made speaker, but that's just me. I would take 1/4-1/3 of that money and buy a good used pair of one of the Prestige models. 10", 12" or 15" drivers will depend on your room and your budget. Put the rest of the money into the rest of your system or (gasp!) the bank. Just my opinion...