I don't know how they do it

LNWR/LMS King George V class 4-4-0. This thing looks just sooo "British." I'd really like to build my model of it for display if nothing else. But can't until I figure out the "round bits" underneath.

"They" in this case being modelers of British railways. And "it" can be translated to mean "figure out which set of wheels to use..."
Some background.
Years ago my late Grandmother went to see her brother who lived in York, England at the time. She wanted to bring me something back as a gift and, knowing my interest in trains, he suggested going to a train show that happened to be going on that weekend and buying me a model I could put together (the fact that I have enough projects didn't seem to enter her mind, although she'd seen the piles of boxes in the basement plenty of times).
She presented me with a wonderful gift - a Brassmasters kit for a OO scale London Northwestern (later LMS) 4-4-0 called the "George V." I always thought it was kind of cool that the Brits kept naming locomotives long after we ended that practice in this country.
When I opened the box I immediately ran into two problems.  
First of all, there are no photos of the model or prototype in the instructions. There's a couple of very rudimentary drawings, sketches really, but there's also a considerable stack of etched parts - and me without an English to American dictionary handy figuring out which part went where was going to present a real challenge.
There isn't even photos on the Brassmasters website. Yes, there's a reference to a set of photos to the almost identical "Precusor" class model. But those images are so small to be almost useless and the model is only shown unpainted. Not a bad thing, but a photo of the painted model would also help. And, let's face it, it's a different engine. And this kit was hardly what one would call cheap.
 
This thing went back into the box and has sat there for more than a decade. 
As you may have noticed from my last post Christine and I just had a wonderful vacation in London and Paris. In London I found a small hobby shop (Ian Allan Publishing - really a bookstore specializing in railway books with some train models - but well worth a visit if you're in London or one of their other locations in the UK - http://www.ianallanpublishing.com/our-shops.htm)
The staff was extremely helpful, as were some of the other customers.
A total of 90 of George V class engines were built, which means they weren't exactly "rare." So I figured there might be a book with lots of pictures, and maybe a drawing of this thing. They had books on every class of locomotives you could think of - except the George V.
At least today we have the internet and I can, and have, Googled pictures of the prototype. And I found a few. 
But there's still a second big problem with this thing. There are no wheels in the kit. That's not unusual - seems a little strange but we have plenty of craftsman freight cars and the like that don't include wheels.
Worse, there's no indication of what kind of wheels I need, or who might offer same.
Since I was standing in a train store in England I made the mistake of asking where I could get the wheels for this locomotive.

"What type, EM, P:4, or OO?" was the reply....

All I could think to say was "uh, Round."

I ended up learning a lot about wheels, and the differences in British scales. Deciding which wheels to use impacts how the kit goes together in a rather significant way since P4 requires bending the etched chassis at one point, and OO means bending it in another. At least that's what I able to ascertain from my reading of the instruction sheets and discussion with the helpful staff in the store. But I still didn't get any wheels. (I did buy a considerable stack of books on Irish Railways.)
But "sourcing" the wheels is apparently going to be a considerable challenge.
Made me appreciate RP25 all the more....