These were a version of the J class with a larger bunker, but I found more subtle differences than I expected. Again its very heavily indebted to the excellent WRRC volume on the Rhymney. This sketch represents a locomotive rather earlier in its career than the J class sketch, with the rather unusual long brass number plate.
Note that this one has Ramsbottom safety valves rather than the pop valves on the J. There was a horrific accident with one of these locomotives where a fitter reassembled the Ramsbottom valves incorrectly and locked them tight so they could not release. The boiler exploded whilst shed workers were attempting to drop the fire and three men were killed and the locomotive destroyed. Subsequently the Rhymney had pop valves fitted to all new boilers.
Working from photographs in the WRRC book and in RCTS, here's an attempt at sketching out the pannier tank version of the K class. Curiously these shared a diagram with a version of the saddle tank with a GWR modified boiler, which would explain why I have no volume containing a weights drawing of this variation. There seems little point in sketching out the GWR saddle tank version, which externally had only a different dome and the safety valve cover to distinguish it from the Rhymney days. I think I'm right in saying this was the only 0-6-2 Pannier tank, certainly the only one with outside frames.
Edited by JimC
2nd replacement of images.