We deliberated over a similar decision some weeks ago. See
here - I got some very helpful info
Finally we opted for a fitted dog guard and tailguard. The tailguard pops out easily enough when needed, the whole thing is silent, the dogs have maximum room to roof and over wheel arches etc.
Ours was a dog guard bought new, overstock, from Toyota main dealer; we bought the tailguard from Barjo. I wouldn't hesitate to recommend them, pretty good price, all things considered, and delivery in 2 weeks. You can order a removable divider if you need one or just use a conventional crate til pup is older - works out cheaper if you only need it for a short time.
Check out eBay for secondhand stuff. Search for Barjo, Guardsman Cage, there's a few to choose from on there now.
Edited to say: have you checked the Bring & Buy section on here. There's one in Somerset...