Don't know if anyone has seen this in the tv forum, but Harry has started a thread over there about his decades of experience working in British tv including Doctor Who (Troughton's time onwards).

He has a website too which is fascinating, and is happy to answer questions on his time in the industry.

It can be found here:

http://forum.digitalspy.co.uk/board/...16#post4684716

According to IMDB he appeared in the following ten Dr. Who serials:

With Patrick Troughton:
The Wheel In Space

With Jon Pertwee:
Planet of the Spiders

With Tom Baker:
Revenge of the Cybermen
The Seeds of Doom
The Deadly Assassin
The Face of Evil
The Ribos Operation
The Armageddon Factor
Meglos
(and would have appeared in Shada)

With Peter Davison:
Castrovalva

He also appeared in nine episodes of Blakes 7 and three of Space 1999.