I haven't been following the two Parkin threads this last wee while so don't know what it is like to eat or how it is made - is it a 'chocolatey' slab type of thing? If so and it already seems dry then I suspect the oats will not soften any more and may make it too chewy and feeling dry in the mouth.
So, the question is "How to save the Parkin"? I'm no good with this sort of thing and I suspect grinding the mixture up again in the TMX then 'doctoring' it somehow would be totally counter-productive but it looks like you've gone to so much trouble the Parkin can't be abandoned. It will be good to see what everyone else suggests.