Pleased to hear 'Fraser-Nash' (hahaha) is settling in well. I had the same issue with Barney when he first arrived and had a few broken nights with him whining/barking at being left alone, for the first time in his life, and in a strange place with strange noises!!
I found reassuring him and taking him outside for a 'comfort break' without any interaction but being firm putting him back to his bed immediately and then left, worked for me within a week however my dogs do spend the whole day with me from the start so this may take longer if you can't spend the time with them. Maybe I was lucky, but this has worked with all my pups and rescued dogs for as long as I can remember. They need to learn they are safe in their new home and in their bed, of course, and are not being 'locked in' to a crate. Personally I have never used one so can't comment on this way of training!
I wouldn't recommend letting him upstairs as it will be a forever preference for him and IMHO is the start of problems in the future with his training.
Hope you can get through this unsettling period with Archie soon.
P