The suppliers for the radios and navigation boxes are not listed as major suppliers, they are covered under typical customer specified items at the bottom right.
I will have a look at some manuals to see if I can narrow this down a bit further.
Edited to add:
VHF: Marconi AD160/King KTR 9100
SELCAL: Marconi AD2880
HF: Collins 618S
HF2: Collins 618T
ADF: Marconi AD.360
VOR/ILS/GS: Marconi AD 260
Marker receiver: Marconi type 6403
DME: A.V.Q.70 R.C.A.
Doppler: AD.560
Weather radar: EKCO E190
LORAN: 345A/600T/LRN 700 (note: LORAN 345A not normally fitted)
Transponder: Control unit type SSR 1601/4