Disco1 v8 strange power steering loss and back

[disconc]

Hello fellow LR owners,

I have a good one to tell and looking forward to receiving some ideas before I can take time to look into it.

Last night, my wife was driving our 1998 Disco 1 V8 3.9 auto, when crossing a big puddle of water, she briefly saw the battery warning light flash... then nothing further.

Still driving about 1h later, car was behaving nicely, and suddenly as she was exiting a round-about, she lost the power steering and had the battery and oil pressure warning lights on.

She managed to pull over on the side of the road and called me.

According to her (wish I could have been there to see things by myself), the engine was idling fine, no different noise from usual, yet the 2 warning lights were on and no power steering.

When she called me, telling the above, I though the serpentine drive belt might have gone south, so told her to switch off, as if this was the case, there would not have been water pump anymore... and I went to meet her.

I arrived about 30 mn later, opened hood, and found nothing or everything...
 => drive belt was were it should be
 => no apparent signs (by night) of tear or contamination by any fluid
 => no leaks under the engine
 => fluid levels were fine
 
 I told her to start the car : everything was fine, no more warning lights, power steering back... Damn'it those kind of problems that disappear.
 
 I drove myself the car back home, in case it would happen again, 30 mn trip, 6 round-abouts, a bit of highway, a winding road... running smooth as silk !!
 
 So my problem now is that something had happened, and I want to know what to be able to fix it and prevent any further problem like loosing power steering on a mountain pass road !!!
 
 It was late last night and it is not a daily driver, so will look into it hopefully on the weekend, but now looking for some ideas.
 
 Here are my thoughts :
  => no power steering and battery light on => looking for something around serpentine drive belt
      => remove the belt and inspect it, maybe even replace it
      => check the automatic belt tensioner (but last night, the marks on it were not aligned, so I believe the belt tension is fine)
      => check every pulley to see if any play other than rotation
      => check for any leaks : coolant, steering ??
      
 Yet, I still do not get why the engine oil light was also on... as the oil pump is crank driven, not by the belt.
 
 Also, if the belt was slipping to the point of battery light on, no power steering, yet engine idling steadily with headlights and AC on... it should have made some noise, or smelt burnt rubber but my wife said apart what described, no other different noise !?!
 
 If you gents please have any idea of what happened and what I could have a look at to try and fine the culprit, that would be great !
 
 Many thanks in advance for your help
 
 Best regards from South Pacific
 
 Erik