I had considered that they may be on him and then re-introduced that way after all the cleaning, but I don't think they are that type of bug/mite?
Certainly haven't seen any evidence of them on him at any point, although that is just from surface level observation- he's not scratching or anything like that. He is not hand tame. He happily takes treats from my hand but he is not used to being picked up and handled so I wouldn't be able to brush him. I'm just going to have to hope they are not hitchhikers.
All his food was frozen for 1 week before being opened and has been stored in an airtight tub (with no sign of any bugs in there at all) There is also no evidence of the bugs in his food bowl?! So I don't think they are grain/flour mites. They are concentrated where there is water but as I say, can see them on the plexiglass walls and on the black frame on the outside.
There seem less of them this morning... but I think they are probably just a bit nocturnal!
I haven't done a deep bed clean out for a while (was trying to avoid it as long as possible as he had been disturbed so many times due to vet visits for prolapsed pouch) so wonder if its due to wet area of bedding I can't see? He uses his sand as a toilet, but only when he's up thought the night. I think through the day be is probably a clart and pees in his bed.
All I can do it try my best and cross my fingers...