Struggling to start

They AA came did they test the battery ? it takes 10 mins of driving to top up what you just used to start it,so a flat battery will take longer than 20 mins to hold a charge. if its gone flat then why ? faulty battery or its not charging ? if you can disconnect battery and charge up. winter and cold weather hammers batteries.

 

The green indicator is for that cell only, it does not give an all clear for the whole battery.
If you have had a low battery message on the dash then i would say the battery is failing, at 0 degrees C a battery is only 20-30% efficient.

 

Mines doing something very similar to this and it’s been plugged in the battery conditioner for two weeks and still won’t fire, I’m thinking it’s the starter motor sticking as it clicks but won’t fire, all electrics work as normal still.

 

Get to a specialist battery supplier, and get them to test the cold cranking capacity of the battery, this is often the thing that goes first - and the battery charge when not actually starting the car will show a normal status. It's only when the stress the battery with a cold start that it fails.

If you have a Mk2 Megane I would also check the tightness of the auxiliary connections to the positive battery terminal, the main clamp and the ancillary supply to the cabin, both use 10mm AF nuts on the connectors and I have known a tech/mechanic loosen the wrong one, then find the right one and leave the auxiliary supply loose - this can then cause some shorting during driving that can drain the battery (and sometimes provide some strange failures).

One good thing these days is batteries often come with decent warranties my last one had a five year unconditional one so when it failed after three years of hard use I was pleased, and a little shocked, when the suppliers shop manager told me I had nothing to pay