Non starting woes :-(

[Midwalescustom]

Afternoon everyone.

Owner of a 2015 2.2 Custom. Recently the fuel gauge decided to pack up on me, empty and 0 miles showing on the display etc. Lived with it for a few weeks but had enough. Got myself a new fuel sender unit inc tank pump etc and fitted it. However, since fitting it the van has refused to start since. In tank pump isn't buzzing at all.
Had the van plugged into diagnostics and I'm getting faults with the fuel sender, primary fuel circuit, fuel pump relay, high beam relay, horn relay, ABS wheel speed sensors and various door lock actuator issues. None of these have been an issue until now, although I did notice the last few weeks the central locking being hit and miss.

Horn works, main beam work. But nothing from the fuel pump nor sender. Checked the fuses under the bonnet, fine. Swapped relays, no change. I'm guessing the BCM has a fault but someone else is suggesting ECU.

Any input at all folks, please and thankyou.