I've had a go at 58xx No. 5809. I think the prototype is probably unique for retaining "GREAT WESTERN" in full on its tanks until the 1950s, despite having a top feed fitted. There is a photo illustrating this currently on eBay, but it can also be found on Page 6 of the "Railway Liveries - Great Western Railway" book. The photo is recorded as being taken in Bristol on 5 March 1950.
Interestingly, it does indicate that the Dapol model of 5809 in shirtbutton livery probably never happened!
Here is my approximate recreation in monochrome, as well as a colour photo. It's based on Dapol's 5811, with top feed and whistle shield added from the spares box, single ATC box behind the cab step (think that's what it is), pipe removed from cab side, tool box repositioned and front steps modified. Plus a bit of weathering - obligatory when it hasn't been repainted for at least 16 years...