What makes you think it's the ECU? It will most likely be old wiring. They can reset if you get a poor power feed which can lead to all of the lights coming on whilst you're going along. Still doesn't mean it's the ECU.

As for them being archaic DUR they were designed nigh on 30 years ago - what do you expect 50nano metre circuitry?

Perhaps you should consider buying a newer car mate if a Mk3 Escort is too archaic for you