Any European keepers here? Where do you get your large enclosures?

I live in Belgium and I'm considering the adoption of a BCI. Many of the animals available at local rescues seem to be young-ish, so not urgently and desperately in need of a humongous enclosure, but I want to make sure that down the line I won't have too many issues with finding a structure where an adult could comfortably live. I'm looking online and I cannot find many options for enclosures longer than 150cm. I think there might be something interesting in the UK, but with import taxes etc. it might not be worth it... Ideally I'd like to get an enclosure in PVC; my second choice is glass. I guess it wouldn't be too complicated to get a custom made wooden enclosure, but is this material any good for boas? What would I have to use as coating, in case?