Looking for advice/knowledge/guidance...

Purchased a 2nd hand RRS l320 2011 woth 125k miles only 2 weeks ago. Car has been a dream with no issues until last night. Whilst travelling along at 70mph on an A road I felt a judder for around 15 seconds that got progressively worse. The car slowed down and showed gearbox fault / low battery on the dash and came to a stop. Very mild smell of burning plastic and car wouldn't restart - the starter motor/solenoid could be heard engaging but the engine wasn't firing.

Car has been recovered and I'll get it to a garage today hopefully but just wanted a heads up as to what to expect? Could it be as minor as a low nattery issue or is that wishful thinking?

Cheers

My bet is the Alternator has failed and the battery ran out of juice. 2006 2.7 TDV6 HSE in Cairns Blue.