Just done the timing chain on my 4.4 M62 but after trying to start at first
It now just turns over and don’t fire if I let go of the key
It still turns over for so long then stops
You can smell the fuel so it’s not that

Ignition? Check for spark and verify that coils are getting voltage.

got a spark on number 1
and I take it as its picked up off the flywheel that should not have moved

Is it possible that you have the ignition timing 180 deg out? get no. 1 cylinder on compression stroke and make sure thats when it's firing not on the exhaust stroke. I've seen exactly this situation on an old Rover V8, I bough it as a non runner, fixed in 5 minutes LOL.
I dont know how the ignition and injection sequences are run on the Rangie so I may be 110% WRONG! BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

If you have a spark and fuel pressure, you can test fuel pressure by pushing the schreider valve in on the fuel rail but cover with a cloth then timing could be the cause as already mentioned.

Did you use all the timing kit for the cams and trigger wheels ?
If the immobiliser had kicked in you wouldn’t have spark or fuel.

Did the injectors all plug back in ok as they can be a little tricky ?

The cams stayed locked all the time with the numbers on the cam flats facing upwards?

Have you tried any diagnostics kit ?