And following discussions with the WGLR's technical / historical guru (AKA Neil) I can now furnish you with the full story of how Lyn came to appear on the railway (answer's Gareth's question too).
When the WGLR underwent their loco improvement scheme in the mid 20's, they not only purchased the Corpet No.4, but also TWO Baldwin 2-4-2's which became No's 5 and 6. By the mid 30's the Baldwins were due for a heavy overhaul, No.5 being first into the workshops. With the closing of the Lynton & Barnstable in 1935, the WGLR recruited one of their senior engineers, Mr Denzil Pemberthy. One of Denzil's first suggestions was that when No.6 went in for it's overhaul, it should be re-built to the same specification as Lyn. This would involve a new braking system, new safety valves, re-siting the whistle etc, etc. As she was due to re-enter service on the second anniversary of the closing of the L & B, the board decided that it would be a nice touch to outshop her in Southern Green as a tribute to her lost sister.
The re-build was a complete success and No.6 came back into service just in time for the dark clouds of war to spread over Europe. Traffic on the WGLR increased thanks to the need to supply No.41 MU at RAF Ffynon Garew and no time could be found to re-paint No.6 in unlined black. In fact, the prospect of a railway in mid Wales running a loco with "Southern" writ large on her flanks was seen as a positive move to confuse 5th columnists and invading storm troopers from September 1939 onwards.
This theory was to be proven in May 1941 when a Luftwaffe Dornier recconaisance aircraft crashed in the Wetton Valley following an unplanned meeting with a couple of Spitfires. Most of the crew were arrested within minutes, but the Engineer, O Lt Reiner Von Chugger managed to slip the net. On the run for two days, he stumbled across the WGLR just as No.6 passed by and immediately presumed that he was well South of Offa's Dyke. Mistaking Wetton for Weston, he tried to hire a boat and was immediately reported to the local Home Guard. Re-united with the rest of his crew, he spent the rest of the war in a Canadian POW camp where, in search of a hobby to pass the long days, Von Chugger became a world expert in basket weaving.

