300TDI disco refusing to start

Hi all first time posting here so I hope this is in the right place for this. I've got a 1998 auto disco 300tdi and its refusing to start.

The story of what happened for a couple of weeks before I was having hard start issues when it was warm only would start fine when it was cold. I was on the way to an offroad event got on the dual carriageway got up to speed after a couple of minutes of cruising at 55-60mph I noticed with hardly any throttle it was chugging black smoke out and i have very little power so pulled over where i could at this point it was still idling id say a little rough but still running on its own, i turned it off to have a look around it and that's where it died.

It still cranks fine just doesn't fire even took down 3 cans of brake clean and 1 can of easy start.
things we have tried
replaced the fuel filter
checked the lift pump is still pumping
fuel cut solenoid
checked the turbo no play and spins
see video for it trying to start seems to be pulling a lot of power as the battery isn't the best but it was hooked up to another can and a booster pack.

https://youtube.com/shorts/BiPpIYPzpjQ

Checked timing case breather hole for presence of black dust?
Checked for presence of fuel at injectors whilst cranking it over?

lynall said:

Checked timing case breather hole for presence of black dust?

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+1