[Hybrid tellies]

Both Bairds 30 and 240 line mechanical systems were short lived and were killed off by the BBC'S decision to adopt the then superior Marconi/EMI electronic 405 line system in 1936.
Apart from Russia who lay claims to having invented the television I do not know of any other country in the world that persued the mechanical system.
After the 2nd world war we and a few countries carried on with 405, the America's had already gone to 525 lines then introduced the NTSC system in the 1950's. The rest of Europe adopted the superior 625 line system.
After trials with the NTSC colour system on 405 we sensibly went to 625 lines and even better went for the PAL system. I do not think any other country that used 405 lines upgraded it to colour. Like us they switched to 625 lines and used PAL.