Skoda rapid hatch back 2015

My Skoda lost power / lymph node on the motorway and the defect glow plug system warning light came on flashing on and off I couldn’t go about 30 mph 3 weeks ago , I manage to taken to one garage they couldn’t find the fault . It’s now at a second garage and awaiting diagnostic and hopefully they can fix the fault. I’m just wondering if anyone has come across this fault before and could give me some reassurance as to what it could be please ? 

Edited 13 October, 20241 yr by Baz90