Locked car using keyfob, came back and keyfob wouldn't work. In the end had to call services out and they hotwired it for me so I could get home. Been to local dealer and he says batteries in key are ok and gave me some advice on what to do i.e. switch on, press bonnet switch, etc etc. But doesn't make any difference - anyone give me some advice on this please.

 

You are going to need the dealer scan you ECU/ alarm system to verify the fault and get it corrected.
Usually if the alarm acts up you can just reset it by locking and unlocking the truck slowly 3 times. In your case, sounds like that isn;t going to work.
Let me know what the end repair is.
Mike