Dougy it was definitely FV439 in two formats:
Carrier, Personnel, Fulll Tracked, SAS/SMC FV439 Ptarmigan -Asset Code 0736-3000
Carrier, Installation, Ptarmigan/Triffid FV439 Radio Relay Access (Tracked) - no Asset Code quoted
I am not quoting this from some military author, these are the deisgnations used in Army Code No.12123 Part IV 1999
Ptarmigan replaced Bruin.
Bruin came into service in 1967.
Ptarmigan design began in 1973.
Prototype Ptarmigan was introduced in 1978
In 1980 the contract was awarded to Plessey to introduce the system over a 4 year period.
Officially entered service in 1985.
In 1987 contracts were awarded for the second phase of the system.
Triffid was the UHF radio relay (RR) link within the Ptarmigan system & contracts were awarded in 1987.
Given the complexities of the system, it was not going to all fit in a FV439. This would explain the different types, for the RR side or the line use & switching. I have to say I am rather overwhelmed by the complexities & versatlity of the system!