I'm sharing my experience in case it helps anyone else.  My car is a 1.4 8v.

 

Some time ago the ABS and Power steering warning lights came on.  The Power steering light could be persuaded to stay out if I paused long enough between switching on the ignition and operating the starter for it to extinguish.  This didn't work in colder weather when it refused to go out until I'd covered a few miles and then stopped, switched off and re-started with the pause.  The steering was heavy at low speeds, and a low speed swerve (once) left me with very sore shoulders.  The ABS light stayed on come-what-may.

 

The code readers (mine and my local garage's) showed failure of the rear LH sensor, and no communication from the power steering.

 

The garage swapped the sensors, RH for LH which made no difference.  They then tried a new LH sensor, also without improvement (that went back to the dealer!).  I checked all the relevant terminals and they followed the cables through but found no break.

 

Some months later I was no further forward. Fortunately I was recommended to an auto-electrician who seemed to know what he was doing.  He found several breaks in the CAN databus cabling and replaced the entire length for £90, doing the whole job in around 4 hours.  About the cheapest possible outcome. 

 

I've covered around 1000 miles since without problem; I like my car again now!

 

If you've got similar issues and are in South Wales, Alun at A & A Auto-electrical in Swansea SA1 impressed me.  (I have no other connection with him or with the business).

 

I hope this helps someone. 

Impressive, a decent auto sparks is a rare and beautiful thing.