John Atkinson sure likes the speaker; it’s his reference.
Of course British audiophiles, with their typically small listening rooms, are willing to forgo deep bass altogether. 50Hz? That’s mid-bass. The bottom note on a 4-string bass (the E string played "open") is located at 41Hz. Any loudspeaker that cannot reproduce 41Hz at full volume is imo not a hi-fi loudspeaker. By the way, the lowest note on a pipe organ (the bottom bass pedal) is located at 16Hz.
The LS50 has a 5.25" diameter "woofer". I have a pair of speakers which use the 5" KEF B110 as a midrange driver, which is what it’s good for. A 5.25" "woofer"? Surely you jest! IMO the LS50 is a midrange/tweeter satellite in search of a woofer. I recommend a Rythmik Audio sub, which reaches into the teens. The combo should make a killer full-range loudspeaker!