These were saddle tanks with double frames. Five were built in 1891 by the Vulcan Foundry. They had started life with a polished brass safety valve cover as well as the dome, not to mention elaborate lining out. As shown here the lining is omitted completely and its intended to be a post WW1 configuration. The frames are rather different to the general run of 19thC RR saddle tanks. By GWR days three had been converted to L1 Class 0-6-2ST, one of which had already been withdrawn.
The two remaining 2-4-2s were numbered 1324/5 and acquired GWR safety valves (and cover) and other minor features, and the air brakes were removed. They were scrapped in 1928. So there's really not much difference between the RR and GWR configuration. From the few photos I've seen they didn't have any GWR lettering on the tanks, which wasn't unusual for saddle tanks, not that these sketches are intended to portray accurate liveries.
The sketch looks very bare between the leading and driving wheels to me. I think in real life the connecting rods and valve gear would be filling that gap. I noted with some amusement - if I interpret the drawings I have correctly - that the leading wheels appear to have bearings in the outside frames only, the driving wheels bearings in both sets of frames, the second set of drivers just the outside, and the radial trailing truck only frames inside the wheels.