On the Mk 5 & 6 escorts it is VERY common to find water making it's way down the A-pillar onto the tracks in the fuse box, and the soldering looks like it has been done by a trained monkey anyway!. This could cause a whole lot of very funny faults. My friends Escort had the washer jets come on for no reason, stutter at 4k RPM, Sudden stalling of the engine - then it fired up again?!?!? Window switches controling the wrong windows, e.t.c, e.t.c So if the voltage regulator doesn't fix it, that would be my next bet.

Hope you get it sorted