When the car is cold and I rev up to and beyond 2k, the battery light flickers on but quickly goes off. Is this anything to worry about?

Battery / alternator issue usually. Diesel or petrol?

Diesel.

Could be the regulator diode in the alternator but i doubt a garage would replace just this item unless it is a piggyback item on the alternator – a simple test at a garage wi diagnostic equipment will tell you the problem

Cool, thanks.

Go to an auto electrician, not a mechanic.

Rectifier on the alternator, dodgy earth, that sort of thing would be my guess.

check the battery connections are tight/secure..hth

Milage ? Could also be brushes and slip ring if its doing it at revs.

Imo once the light starts flickering its a slippy slope.

Simple checks you can do yourself battery terminals and condition tension of the drive belt then look to auto electrician as poss diode pack.

What car is it?

you are actually driving it? ie more than a couple of miles, i had this with the last car, took it for a decent drive and went away. I had been doing a few very short drives so flattened the battery but never really charging it up.

Charge can be checked using a voltmeter across the battery terminals. Should be about 13 to 13.5v running i expect but may vary with your car. Usually 12 or 12.5 ish if cars not running.((IIRC)) Earths can get corroded too and require a clean up.
Remember neg battery terminal off first, on last. ( might be worth double checking for your car)

you are actually driving it? ie more than a couple of miles

Yeah, I was doing 60miles/day when it started I noticed it, now i’m doing about 20/day and it’s every so often when the engine is cold.

Check engine earth strap. Had same issue in my Fiat Ducato, you need to be careful as it is easy to blame the alternator when its the ECU not getting enough power

If it is a ford get a auto electrician to look at it.

Ford use a smart charge facility which is controlled by the ECU.My FIL had a issue with his focus turned out to be a broken wire which screwed up the charging and every so often would put the battery light on.