Celestion guys who have both (Blues were also made in China for a while) say there's absolutely no difference in tone in new ones regardless of origin once broken in. Old ones sound a bit different to both, because of differences in parts and age. The bits are made on the same tooling. Celestion controls the factory output in China. If you want to pay extra for a made in Britain sticker you can. Anything Nightrain would be Chinese.
I had a Bletchley made 2525 made 2014 - Chinese Greenback. Sounded - like a Greenback.
I had a Bletchley made 2525 made 2014 - Chinese Greenback. Sounded - like a Greenback.