Honestly, the .425 WR is a truly mediocre caliber. Would I use one? Absolutely...but only in a vintage WR rifle. Cannot fathom the idea of building a custom modern rifle in a fairly neutered caliber. The custom brass, the unique bullets, the side clip/feed issues, etc.
The one at Cabelas was a tricky one. I offered $2000 knowing I'd spend $4500 putting a 100% correct, done in UK stock on it. It wouldn't be worth much more than $6500 as a nice, properly restocked rifle.
Now if you want to talk stupid, here's a 4-year-old story for you.
I had the opportunity to buy TWO Westley Richards take-down rifles. A 318 lightly used. And a near-new 425 Westley Richards takedown.
I bought the 318 and used it in Africa. The Take Down 425WR was $10k and I just didn't have the coin for two. Another guy bought the 425 WR.
A year later, the owner of the 425 WR purchased the 318WR from me through an intermediary broker. When we spoke of it, he gave me the news.
"You shoulda bought the 425WR...its been missing for nearly a century. It was Frederick Courteney Selous' 425WR. Its the one he shot chimneys with from his London hotel room."
Yep. I passed on a $10k 425WR that is worth...$250,000 and is probably one of the top-20 most significant rifles ever made.
So if I seem irritable the past few years, refer to this anecdote.