OK. Well, the thing different between yours and mine was the BECM not receiving a valid code from the receiver or remote. Cannot remember exact words.
Looking in RAVE section 86 page 10 (page 1231 overall) it says:
On vehicles up to 97MY, resynchronisation is
achieved by locking or unlocking the driver’s door
using the vehicle key with 30 seconds of locking,
superlocking or unlocking using the remote handset.
The BeCM monitors the condition of the driver’s door
CDL switch to initiate the resynchronisation.
On vehicles from 97MY, friendly resynchronisation
was introduced on vehicles with passive
immobilisation. A remote handset that is not
synchronised to the BeCM will automatically be
resynchronised when the key is inserted in the ignition
without using the vehicle key or Emergency Key
Access (EKA) procedure.
The resynchronisation uses a pick-up coil in the
remote handset and a passive coil located around the
ignition barrel. The passive coil provides a signal for
the remote handset to transmit an unlock signal to
remobilise the vehicle.
I wonder what effect it would be if the pickup coil in the ignition has come loose? The BECM should have got the code from the RF receiver when you unlocked the car but if it isn't picking up anything from the ignition it looks like it probably wouldn't start.
Take it you don't have another key to try in the ignition?
Or you could see if anyone has got an old RF unit you could borrow for testing. I'm sure people will have replaced theirs and kept the old one just in case!