Spencer Banks

Spencer Banks:  

Very much in demand in his youth during the '70s, when he took the role of Simon in the mind-expanding young-person's drama 'Timeslip', Spencer Banks also appeared in the folk-horror 'Penda's Fen', a 'Play For Today' from 1974 which now rubs shoulders with 'The Wicker Man' (1973) and 'Children Of The Stones' as a classic of the genre. With his shock of red hair and expressive, sometimes awkward, features and manner, he was a natural for the role of the loner or outsider. 

In the witness box in an episode of 'Crown Court' 

With Spud, played by Mike Grady, in 'Tightrope'

Beyond these, he can also be seen in good quality fare from throughout that decade including 'Tightrope', 'Lord Peter Wimsey' with Ian Carmichael, 'Village Hall', 'Churchill's People', Dennis Potter's 'Pennies from Heaven', 'The Georgian House' and 'Minder'. In addition, he had a short spell in the popular (with older ladies) teatime soap opera 'Crossroads' which was probably a biggish deal at the time. 

In yet another children's time-travel mystery
serial, this time HTV's 'The Georgian House'

By the early '80s and beyond, pickings seem to have got a little slimmer, though he pops up as a copper in 'Shine On Harvey Moon'. There are a few decade-apart roles including 'Doctors' on TV and the straight to DVD 'Amityville Playhouse' (2015). Whether he was just too much a face of the '70s, or his moment simply passed, it seems he retired from seriously pursuing an acting career. Nowadays he is a much sought-after guest at cult TV conventions, but I can't help but hope that some interesting part is still in his future timeline.

Bonus content:
For a full-on '70s time capsule, I point you to this splendidly mundane oddity:
'Living At Thamesmead' (1974)
      

Spencer Banks-imdb

Peter Greene

Peter Greene: 

† October 28 1945 - March 19 2009

Here's a difficult one. I'm assuming with fingers crossed that Mr Greene is still with us, but I haven't been able to verify it. Things are confused by the fact that there is another Peter Greene in the movies (the American one who played bad guy Zed in 'Pulp Fiction'). 
The one I'm saluting here is the lanky red-headed chap you've seen playing the clueless chaplain of St Swithin's Hospital in ITV's 'Doctor in Charge', or perhaps as Grace Brothers' resident boffin, demonstrating a dummy that drops its own trousers in 'Are You Being Served?'.  

Chrissie's pipe-smoking boyfriend in 'Man About the House'

He appeared in two episodes of 'The Young Ones': as a teacher in a 'Grange Hill' spoof scene with Ben Elton; and as the vicar in Rik's favourite sitcom 'Oh Crikey!'

As the man from the BBC in the 'Dad's Army' skit from
'A Christmas Night With The Stars' in 1972 

The trail goes cold with this sketchy imdb snippet from 2002: 'Works for an independent research company, but still does corporate work and directs local shows.' 

Peter Greene (II) - imdb

Postscript and apologia:

In my initial post, I inexcusably gave him the credit for one of British cinema's finest 'Fwooooaarr!'s as Henry the clumsy ambulance driver in 'Carry On Doctor' (1967). Click here.  This is of course the late Peter Gilmore. I'm indebted to r lewis for the correction.

*Further postscript:

Sorry to hear, via the contribution in comments below, that Peter Greene passed away in 2009