Engine back in, no start

[nznikin]

I have recently put my transit engine back in and wondering if I need to re-pair my key fob? It's been out for well over a year while other stuff was happening so I believe this may be the case?
Some relays are switching on the passenger side fuse boxes, one of them a believe is for the windshield water pump.
To me it looks like the immobilizer is the issue or doing its job i guess...
Video here of the sequence-> https://youtu.be/e-jW6mKuD28

Thanks,
Nick

[gus-lopez]

Mark 7 keys are charged through the ignition barrel so if it hasn't been used for a long while it probably is completely flat.
Inductive charging ,like a tooth brush.

[Altransit]

The key only needs a battery for the central locking buttons, the key chip for the immobiliser is passive, and is read by the inductive ring around the ignition barrel.

If the fault is with the key, or the immobiliser, the LED will flash out a fault code.

Have you checked both batteries under the seat?