Rear windows working, fronts ones aren't...faulty ECU?

Hi......and help!
I have a trusty 1993 TDi Range Rover whose front windows have just packed up within a couple of days of each other......which is ideal in this hot weather! The rear ones work without a problem. I've switched over the switches and the relays between front and rear (no difference).
Could it be the window lift ECU or would this just pack up completely?
Cheers
Rich

Not sure,but this might be of some use:

Fixing non functional rear windows