A little story of what happened during late development of this series, told to me by Phil Swift.
When Phil S took over, Derek Hughes was still there as a consultant. The sound wasn't quite as the new owner wanted, so a little tweak was done overnight. Derek heard the difference I gather and put it down to a pretty major crossover or driver change. All that was done was a change in capacitor type (I'm suggesting electrolytic to film poly prop types). This is a well known 'thing' today, but back then it was a fairly new experience for established traditional designers I believe to get their head round.
So yep, the Spendor S series WAS listened to and dealer opinions sought before proper launch. The Se version suited them better to smaller UK rooms and in some ways, the A series was a visual backwards step imo, although the cabinets are far more solid in the flesh than they look in pictures of these later ones. The current equivalent of the S6 models is pushing £2k now I understand...