6 month old’s fear at parents house

Just looking for any advice on this from anyone else that’s been through it.

We have a 6 month old working cocker spaniel who honestly has been a dream so far (anticipating a tricky adolescence). We’ve spent many nights away with him at family homes and he’s very happy. We’ve stopped crating him because he’s fine to settle and sleep outside it. Might bring it back if teen years are tough.

We’re brought him to my mums house in the cotswolds at the weekend. Staying for 3 nights. Arrived at night time and he was instantly fearful. Tail tucked under, anxious behaviour, wouldn’t go into the garden. We assume it’s because we got there at night in an unfamiliar surrounding…

We decided to have him in our room the first night to keep him settled. Didn’t help. When a car or tractor would drive past he’d hide under the bed. He eventually stayed under there most of the night, getting v little sleep at all.

Throughout the next day he got used to the environment and displayed less and less anxious behaviour as the day went on. In the evening he took himself off to his bed inside while we were eating dinner outside, we happily left him downstairs with the radio on and he slept through the night.

My step dad is a super noisy guy though and the poor pup was spooked again when after we all went to bed there was loads of noise as step dad showered. I had to sleep downstairs on the sofa with the dog in his bed next to me.

And he is now super sensitive to new sounds. He loves my mum and step dad and they would love to have him stay without us but I wondered what additional things I can be doing for him to have increasingly positive associations with this house because disturbed sleep rules out us leaving him with them…

I know that it’s probably because we arrived at night time without a chance for him to ease himself into the new place, so how can I be sure I’m not permanently damaging his relationship with this home and my parents while he’s in this fear period? Many thanks!