Yowch. Are You Being Served was terrible. I didn't think much of Dads Army and Steptoe and Son either.
Better off Ted. Most underrated comedy IMO. Critically acclaimed, and ABC just couldn't find a good time slot or advertise well for it. Also like arrested development it's humor, at times went over some heads. West Wing. Just a great show that I can still watch, any episode on netflix.
Its funny as i love a lot of retro music, love retro games but when it comes to retro tv shows i'm not a huge fan. Have to agree with the OP, Dads Army was 'before my time' so when BBC still showed it when i was older i just didnt really find it that funny, think it was a 'you had to be there'. Bit like Hi De Hi, i loved it as a kid but would i spend some time now watching it on one of the channels ? Hell no. Are you being served again was funny (for its time), again would i watch it years later for longer than a minute ? Not a chance. That 80's style humour i just dont find that funny anymore, now i'm older i prefer more adult jokes/humour/swearwords, everything back then was mostly 'harmless' family fun on a saturday night.
English used to be natural at television, I was watching those shows well past their used buy date as reruns as a kid and enjoyed them years after their issue date. Some have aged better than others but you take them for the era you saw them, comparing them to today's sitcoms where the star will get paid 100x the full production costs of a yesteryear show is a little unfair. And even then comedy as a whole has become very forced, dry and over explained (unless you follow standup which is he generally more independent and less plastic). There's still some good ones around today, but the hit/miss ratio is a lot wider.