In short...

My old Park Assist Module (PAM) got soaked and died.
I tried a cheap Vogue sourced replacement but it wasn't recognised by SDD (v. 167)
Bought a more expensive used L322 version with the exact same part number - AH42-15K866-BE and have just fitted it to the car.
SDD can now see the module, but it's not operational and SDD has only one DTC for it - that the VIN number is wrong.
I've tried SDD configuring the unit but the SDD routine says the VIN can't be changed with that routine.
I've also run the SDD diagnostic self test on the PAM and it works OK according to that.

Is there some other way to over write the VIN in the PAM so it will start working?

Not exactly an answer to your question but I replaced mine (which was missing when I bought the car) with one from a Discovery 4.

It was a straight swap without any reconfiguration. The only peculiarity I had was a couple of faults dating back several months from when the “new but used” PAM was installed in its original vehicle. These cleared without a problem using the Gap IID tool.

From my experience the PAM was not VIN coded and configuration was not necessary (possibly because the number of parking sensors on the donor vehicle was the same)

My vehicle is a 2011 4.4 TDV8