here's another one

when car is left cold for a couple of days, comp briefly says hdc fault system not available, then after running it's ok. could this be low battery? (before i buy a new one)

Taa!

Yes, that's definitely a telling sign of a battery not providing enough juice upon startup, causing random fault messages that usually - but not always - clear shortly after the engine cranks and starts. Sometimes very cold weather causes it, but it's more likely your battery is on its last leg, or the alternator is faulty. Get both checked asap. 

New battery dude.
- I got one last winter. Sorted it out. 2022 P440e AB

new bat tmoz then, cheers

Also pay a visit to your local dealer and get them to clear all the fault codes from your vehicle memory. Low battery voltage will throw loads of false fault codes which could hamper future investigation into any genuine problems you may have. Arctic Frost TDV6 SE. Aspen Leather, Cherry Wood, Privacy Glass, PTI, Tow Pack, Mudflaps, Tasmods, a new Fuelflap, a RRSport.co.uk umbrella in the boot & a RRSport.co.uk sticker on the rear glass.
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