Tekna 2018/9 variants have the newer looking LED DRLs with an elongated light bar across the top of the headlamp unit, if it has the older > < type DRLs it's not a Tekna.

Unless you have a Tekna variant or paid extra from new its most likely a halogen. If the headlight output is a warm colour and not very bright then it's definitely a halogen. Check out the Autobulbs site too, they have a reg no lookup and offer and describe the various options including those aimed ...

on the other hand, worry about it when you actually need to top up and you may never need to buy any at all! that's been my approach with my j11b and haven't needed to top up once in 4 years

there are old and new images on page 2 of this thread

I'm no expert at all defc0n1 but, to me, this sounds more like a gearbox failure that you are describing. I had a gearbox let go on my 2009 at 110,000 miles, I lost 6th gear, 5th kept jumping out to nothing too, lost drive but no whining nor Braking effect for me.

that's not too far off what I'd expect from mine, can get just over 50mpg on a good run, sometimes 51/52.

fog lights... immobiliser... ejector seat?

Am wondering if there is any prior indication that its about to let go, or its fine one moment then not the next?

here's a picture of mine after the 1st repair:
are you looking at the same wire? mine is a 2019 car so things may have changed.

that picture you posted looks iffy to me, it might be worth someone wiggling it whilst you sit in the drivers seat and watch the dashboard lights. there are 2 very thin wires going into that plug and your also looks like it's lacking weather proofing. And no, no ABS specific messages or lights showe...