Chinese MGTF LE500 Unlocking/starting problem showing error codes P0601 & P0601P

Hi guys
Went to start my MG today (last used two days ago) and initially the central locking was playing up, clicking etc. Roof was down so entered via the pop up lock on passenger side and opened driver door from internal door handle.
Put key in ignition and all the warning lights were clicking/flashing and the gauges all flickering and needles ‘trembling’. Suffice to say car wouldn’t start.
I have a basic OBD2 reader which gave an (already known) P0420 code as car is de-cat (so MIL light on too) but 2 further codes were present:
P0601
P0601 P
Resetting didn’t work.
Other recent problem was the rear cooling fan ran on a long time after car stopped even though the oil temp gauge never goes over 70 degrees.
P0601 states “Internal Control Module Memory Check Sum Error”
My car battery is on a conditioner on timer and a recent voltage output test showed 13v.
Can you please advise next steps to solve the issue please 🙏

Check the earthy side of the battery & give both +&- terminals a tweek. Worth giving the battery a proper load test & nip up the grounding lead to the frame.
I’m out after that, my car is much older than yours & I’ve no experience of the 500 even though it’s little different to the tf of which I have a little experience.
M

SOLVED - a grandson had been sitting in the car flicking various switches. I hadn’t noticed the interior light was on and it drained the battery faster than the trickle charger was charging 🥴A full charge overnight sorted the problem!

PS the OBD2 reader was then able to delete the error codes too!

Those pesky switches are so easy to accidentally turn on. I had similar and would recommend using LEDs. Easy, cheap and avoid trouble.
(I have to use a Disklok with a long arm).