In some ways you can't blame him, they are one of the biggest piles of poo on the market TBH.
As you have found it does only have one PCB in the door, the later machines do have two.
Lights 1 + 4 are supposed to signify a software error, the electronics are woeful on these machines. Some of the PCB's are quite cheap but the ones for yours are over £60 ex vat.
There are two different ones and the full serial number is required to identify.
Firstly though you should run your megger over the internals, the heater in particular can throw up spurious error messages if it is down to earth, although yours has the better 'in tub' heater as opposed to the tube type which is less reliable.
That which can be asserted without evidence, can be dismissed without evidence.