Listening to a hot rod MC240 as i peck out a somewhat informed reply…. i vividly remember it coming in the door in 1965…. I’m currently running some TAD ME-1K with a JL sub but the amp is capable of a lot…you can see it paired w all sorts of speakers from ESL-63, Cornwalls, etc in my virtual systems pages. Since you are UK based, i would get the best NEAT you can afford keeping in mind a well sorted MC240 will typically make 52wpc , or any of the 200 ish mm BBC spec speakers. you also might be shocked how good a NAIM preamp might sound w 240 ( i actually know…vs just reading about it… ditto the 110Z
also do not be afraid to use Mullard in the front end of the 240. Do absolutely make sure the filter caps are in good shape… the power transformer is… rare…and near unobtanium….
have fun. enjoy the music