Eric Longworth, who played Wallace in the 1975 TV adaptation, died recently, aged 90...

His son mentions his uncanny resemblance to "the killer.."
The Stage / Features / Eric Longworth

more obits...
Obituary: Eric Longworth - Liverpool Daily Post.co.uk
Eric Longworth: actor who played the town clerk in Dad’s Army | Times Online Obituary
Eric Longworth R.I.P. - Britmovie - British Film Forum