Rattigan is lovely!
He does look a bit stressed to me.
I would try setting up a play area or play pen with lots of toys to explore, a wheel to run off a bit of stress or energy & you could scatter a few small seeds or treats around for him to find, you can sit in there too but just let him taking his time exploring & getting used to things for a while.
I’m not a fan of using the bath tbh, I think bathrooms can be quite overwhelming for them, if you can do it in the room where the cage is & things are more familiar that’s probably better.