We have Trans K9 crates, https://www.transk9usa.com/
, in our smaller vehicles and we love them. They are a little pricey, but they are tight and never creak or rattle from road vibrations and they are made to fit your particular model of vehicle.
I would image that you would have to pay a pretty price to have them shipped from the UK! I would think that there would be a company that does the same thing here in the states?!
I use a variety of crates in the car depending on the need and dog. I have a 36" wire crate for traveling with a bitch, but use a 40"/500 sized plastic airline crate for my male. I drove Ford Expeditions for 13 years and could fit those two crates side by side. Now I have a 2019 Honda Pilot, and would need to get one narrower crate to do the side by side.... but found that a 21" wide crate is really a squeeze for any decent sized male.
I take my crates in and out frequently, so as much as those built in type crates look really nice, I don't think I could take them in and out regularly. I would assume that they weigh a freaking ton!!
Mary Jo Ansel
AKC GRCH/UKC CH Fitzmar's Command A Minute CGC "Harvard"
Fitzmar's Victory Hop Devil RN CGC "Jezebel"
Ch Jalyn One Moment Please "Mabel"