I paid good money for mine as have a few others. These two just ended up in the wrong venue.
IMO, they would've done way better on Ebay. Some of the best money I've seen for an XR was had there.
Once it was on Ebay, I'd definitely give Barnfinds and probably BAT a heads up.
I wouldn't even want to Cosworth the Bonham's XR... it's too good of an original car.
But there are examples out there that are slightly less good that would be a perfect starting point.
I go back and forth over whether my car would be that perfect starting point, as I'm not a fan of the C3 that's in it at all.
If I did Mike's A4LD or a T5 manual swap (making it no longer original) I would also consider taking the Cossie leap...