Interesting discussion. I've been going through the whole WR-R thing too this year, wanting something lighter for Morocco and maybe Sahara. I change bikes most years. Tried an overpriced WRR test bike from a dealer and loved the response.
Had a CRF-L (in the US) and have a KLX hack (carb) there too.
As the OP concluded - hard to find a decent WRR in the UK for the money, and while there are a few more in Europe and re-reg'ing in UK is easy, the hassle in finding a good used one and expense of riding or vanning one back all add up, unless you're buying new or near new from an EU dealer. Tried with a couple in DE, but they lost interest.
I'm sure I looked, but didn't spot the great Polish price - bargain - like Ozzie. May have tried there had I seen it. Saw as low as < £5000 new in Italy (may have been an X - all the same to me).

I considered a UK KLX (efi) too. New price was below £4k last time I looked and as said, much better suspension than a CRF and prob as economical and as low, but aftermarket tanks are small, not in UK, and I suspect CRF-Ls are more reliable and a bit better made.
Even the OE WRR suspension is not so hot. Depends how you ride but the rear shock is under damped. The re-valve is a well-knkwn tweak (explanatory vid). Other issue was stator on the 08s which is a recall, spare fuel pump not so expensive and I'll watch the chain wear on the swingarm guide.

Anyway, have accumulated a giant IMS tank, got a bash plate and other bits and have an 08 being put together by Hyperpro in NL. Never had so much trouble sourcing a bike (aka: initially too stingy to accept the age/price ratio - same story with DRZs). Let's hope it was worth it.

Either could be a truly perfect dirt-biased overlander.
Bit more poke for a little extra weight, so closer to 690/CCM but with the benefits of Jap design.

Each to his own but for long-haul RTW I wonder if a WRR might be a bit wasted. Seems to be a unique bike - a Jap tralie with European-like performance, but perhaps better suited to shorter duration BAM/jungle/desert type off-roading. Cant go wrong with the best CRFL or KLX you can get in the UK for your money. Subframe I noted was chunkier on my US KLX (summary here). Mine also has clever adjustable dog-bone joints. Never seen those.

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Morocco Overland 4 (2025) • Trans Morocco Trail