Thanks to all for your responses.

I have tried turning steering wheel from End to lock. .....no luck.

there is no clicking sound , so plastic gear in transfer case should not be issue ?

Had similar issue

2005 Facelift 134k miles, runs ok .

However, 4x4 light was on at time of MOT.

It Failed MOT on 12/03/19 because:

"Electronic stability control warning lamp indicates a fault"

However, when 2 garages ran Diagnostics, they could not diagnose fault in order to fix it.

I do ...