Lol, I have form with the aul weedspray so!
I built a few of them. The first one was a stanier cut and shut, which involved two chassis' married together. Not recommended. Second one was a styrene overlay on a gwr 60' coach, but when finished didn't have the girth, nor the roof profile that that the Irish "wide assed" girls do. Was nearly 4mm too narrow and unconvincing.
The last one is being worked on - faithful down to each replacement panel and rusty hinge for a certain member on here. I've just completed the kit for the etched overlay for the MK1 BSK, after making a half dozen of them, but that's for another post. I really need to do a workbench update.....