Intermittant Instrument Cluster problem.

[Ska]

Hi All,
Hope every one has been well.
It's been a while again since my last post but we'll save that for another time.
My issue is with the instrument cluster on my ’97 2.8 sport (ACK, CJY), on a couple of cold mornings when the ignition is first switched on there is no life from the instrument cluster, i.e. No dials, no DIS, no fuel gauge or temp. gauge? This naturally scarred the crap out of me so I disconnected the battery earth for a minute and reconnected it and hey presto the display returned to normal. I'm of the thinking that I may have a dry joint on the cluster PCB?
First point of call was to give my self a heart attack by calling the Stealers who said it needed a new instrument cluster at around £1000! Because apparently it needed to be coded to the car?!? I then did the sensible thing and checked the A8parts shop which has a note for preface lift cars saying that they
don't need immobiliser coding.
So to my question: what is the deal with buying a second hand unit?
Apart from getting the mileage corrected is there any other "coding" that needs to be done? I'm assuming the part numbers have to match but apart from this, is it just plug and play?
Sorry for all the Q’s can’t get access to my Elsa win and ETKA as PC is temporarily buggered.
As ever any help appreciated.

Ska