Help for newbie please

[smurfitt]

Battery wasnt holding charge in my 2011 berlingo van B9. Took it to local fitter and the fitter disconnected the old one from terminals but didnt seem sure about how to get it out. His mate told helped hom remove the casing and bracket. He then went to get a new battery and fitted it. Heres where the problems start. Turned the ignition all instruments lights on dash and electrics all working but van doesnt turn over; not even a click. They locked and unlocked central locking but still nothing. They checked battery was fitted correctly and all fuses were ok. Basically left me with a van that wont turn over and said they think the immobiliser is stopping it from starting. Electrician friend said it would still turn over if that was the case but just wouldnt start. Eventually got it recovered and towed to a local garage. They did a diagnostic check and said a list of faults are showing yet before I took it for a battery change there was absolutely nothing wrong with it. I dont want a garage to rip.me off by saying this that and the other is wrong when its obviously something to do with the battery being disconnected for a while. Any advice would be much appreciated.

[Sol]

Hi, you can try a BSI reset. Probably should be done on changing the battery. Also did they disconnect any cables from the large battery connector plate at the front and not put them back?

Anyway here it is:

https://youtu.be/qQwhzngHQw4