Airbag Warning Light

[Culloden]

My 93 Aero convertible failed its MOT with and ACU permanent fault. I sent this off to be reprogrammed but it did not help. Was then told to send off a 2nd hand one with the original and the data would be swapped over, but I am having problems finding an 04 unit of the right part number. I then enquired about a new unit and was told that you can't use a 2nd hand unit anyway!!
Does anyone have any reliable solutions or information about this fault

[9-3 Aero]

Not being familiar with your MOT tests, to whom was the ACU (which I understand as the Airbag Control Module (ACM)) sent for reprogramming; someone qualified for programming of Saab modules?

There are more than 160 Diagnostic Fault Codes related to the Airbag system, are any of them noted in relation with the statement "ACU permanent fault"? If not, would one step in resolving this issue to get a readout of fault codes, thus maybe get a more precise answer to in which way this ACU fails.

With regard to part number (P/N), do I understand that it is MY2004 which is question. Looking in the EPC are 4 P/Ns pertaining to MY04, dependent on chassis number and obsolesence. What is the P/N on your original ACM, and is the chassis number lower than 46020385?