The 101FC now owned by 101Ron had been rebuilt by BAe, and when owned by a previous owner in the late 90's (purchased as a direct release from Defence) also had it's matching trailer built by BAe. I seem to recall it looking very similar to these , but I will have to dig through some old photos to see if I have recorded it.
The mid-90's rebuild/refurb of the 101 would have occurred after the retirement of the Rapier system, and/or the introduction of the 6x6 Air Defence Perentie, so perhaps the trailer was designed as a re-purposing of the 101?