Spendor SP100R2 still a relevant speaker?

Yes, one is a Tannoy and the other is a Spendor.  

Both should have pretty rich midrange and run on the warm side, so different but not so much.

I have heard SP100’s many times, a good friend owned a set for many years, it is a terrific speaker on many kinds of music. Kind of doesn’t do anything wrong, gets alot right, and always sound approachable and makes nasty recordings sound decent. They are pretty efficient so using a good tube amp can get the vocals to be super sweet. Spendor as a company has been poorly handled in this country in recent years, maybe they are making a comeback now. I still have my Epos M22’s and there have been many times I have been tempted to go for the Spendors but the price keeps going up. The speakers have always top notch especially their original heritage models.

Tannoys have been around forever too, perhaps even more old fashioned than Spendors. When I have heard them at shows over the years, they kind of struck me as sounding somewhat like a refined horn-loaded speaker, dynamic but there can be some honky affects on some female vocals that can creep in, but maybe it depends on setup. They too are very efficient, so many Tannoys owners use tube amps to drive them.

Simple.

Listen to both.

Buy the one you prefer.

One man's opinion on this means nothing to you.

You have your ears and he doesn't

What do you mean by relevant? The Spendor classic 100 is still in their line up!

Classic loudspeakers – Spendor (spendoraudio.com)

Yes, very much so.  Many people prefer either the Mk1 or the Mk2 to the Classic 100, as there have been subtle shifts to its voicing over time.  If it's a good deal and appears in good condition I would pounce.