Check the radio suppressor relay. It is actually an injector relay which was put into the circuit to stop the injectors interfering with the radio.
It is usually mounted alongside the cooling fan relay which, up to 1991, was the same part number. The easy way to check is to switch the two relays, assuming the cooling fan relay is OK.
If there is doubt about the cooling fan relay you can jumper the two larger wires leading into the radio suppressor relay connector. If the engine then is able to start, your relay is defective. If not, your problem is elsewhere. Don't leave the jumper in place or your battery will discharge: this is for testing only. If you do use a jumper and the fan starts, you've jumpered the wrong connector.
Work was good - retirement is better.
1996 850GLT 2.5 20v Estate Manual.
1995 Peugeot Boxer 2.5Tdi Autosleeper.
1984 244DL, Manual, Beige.
1987 744GLE, Manual, Green.
1991 960 3.0 24v, Auto, Silver.
1994 940T Wentworth, Auto, Blue.