There is jack all of value in a DPF, its just ceramic composites, its CATs and SCRs that have valuable metals in them.
And you shouldn't need to do anything to keep the ECU light off, its only a temperature and pressure sensor which can be left connected
I still say you need to get those injectors sorted, your piston failure was not foreign body caused, its overheated
I have been trying to get my head round that level of overheating. I assume that the injector must have been pissing fuel in all the time
I also assume that it would be obvious to any normal driver that something was seriously amiss .
Is there any chance that something wiring or ECU related could cause this issue? I have this notion that some piezo injectors have to be turned off after they have been turned on. If the wiring to one of those piezo injectors becomes faulty then they can get stuck open. (Not saying that Astras have this type of injector BTW)