I'll eat my old boots if the ECU is faulty - when they go bang the lights go out altogether.

Have you actually got the dipstick plugged in at the top?

Is the petrol tank connector still plugged in under the back seat?

There could be a bad joint on an earth cable in the loom somewhere - the earth points are shared between more that one light.

You can simulate a wear indicator by plugging a resistor into the socket at each front wheel instead. I forget what value is required but I can find out.

To be honest it wouldn't be a Mk3 Escort if you didn't have a few of those lights flashing