I had the 'no radio' today. After following the electrical diagrams (1992), it seems that the radio gets it feed from the seat heater relay, hidden up in the passenger side fuse panel, LHD which powers the No. 7 fuse.
This is a 5 prong 30 amp metal cased relay with the diagram part number LB283. . This relay switches to both 87 terminals from open.
Anyone know the Jaguar part No ?