XF Sportbrake starting woes

[MrKetch]

Just before Christmas I tried to get the rear tyres changed to be told that both wheels were cracked (thank you Devon Highways for not fixing pot holes) and that I needed new ones. The car was parked on the drive while I sorted out new wheels over Christmas. Went to start it to take down to the tyre place when they turned up and dead battery. Couldn't charge it so it was swapped under warranty. Charged the new one and popped it in the car (well grappled it into the boot) connected up and the fun started. Car wouldn't start, wouldn't lock, mirrors refused to fold and various other oddness. ODB2 reader showed various battery related issues so used SDD to refresh the BCM but no luck. I run the immobiliser program which sorted out the locking and mirror issues but it still will not start. It looks like it is going to start, dash lights go on and turn off but as you take your finger of the start button it all just switches off. There is no attempt at all to start the engine, no clicks etc, it just turns off.

I ran some diagnostics with SDD and the following code came up:  B1B33-87 which means "Target I.D. transfer - Missing message" and it is reporting that it can not communicate with various modules such as the ABS, GSM, PCM, RCM, TCM and the AAM. My understanding is that the ECM isn't talking to something else to initiate the start up of the car. Can anyone suggest any solutions? I am desperate to get it back on the road as getting to work has become a daily challenge.

Thanks in advance.