Intermittent fault and resolution

I thought I'd share the following in case it helps any other owners - headline: a dodgy battery can cause strange problems.

2017 Octavia SEL Estate 2.0 TDI 4x4.  I got a yellow 'preheating unit' warning light accompanied by the car going into 'limp home' mode - awful, could hardly pull away from traffic lights etc.  Problem went away an hour later, Skoda garage investigated - nothing wrong.

A couple of weeks later - exactly the same problem - again it cleared itself - again the garage found no problem.  Luckily the problem re-appeared when I went to pick it up from the garage - this time it wouldn't start.  Battery failure.

Skoda replaced the battery - no problems since (fingers crossed).  Now I'm hoping it was just the battery, not something else that caused the battery to fail over time.

Anyway, I hope someone finds this useful if you are hunting down a frustrating intermittent problem.