D2 2004 td5 no start immobiliser

Evening all I have just brought a d2 td5 2004

I drive the truck to my place
Had no
indicators
Central locking
Pin it down to the bcu being no good.
Got another bcu from scrapers no key or fob
When fitted all the indictors centre locking all worked again
And this is where head ache started
The immobiliser kicked in. I can get in the new bcu with laptop to get the eka code from the new bcu did the door thing unlock a million times then lock then unlock wait 5 min and nothing

Tried the old bcu back in and still no start now but the bcu won't let the laptop in it to get the eka from that one I have email main dealer and phone them no answer and no email back

What is the next steps for me please
New key for the new bcu
Whole new lock set
or get it mapped with the immo turn off

or burn it twice
many Thanks gav

Update
It's runs
I put old bcu in
All the same problem
No hazards indictors

Go to crank it nothing

Pull the starter relay ignition on and put a live to the relay slot cranks and starts and drives

Had running for ten minutes
Autel still won't let read old bcu
But does read the new bcu

Turn off try to start on key and nothing