As I have made clear on more occsions than I either can or care to remember here, I have no idea what a "plinker" is, but it seems that, if Jonathan Powell's repertoire consists mainly or entirely of music by them, then Bach, Beethoven, Chopin, Liszt, Alkan, Brahms, Albeniz, Busoni, Granados, Rachmaninov, Godowsky and Medtner all fall into this amorphous and as yet undefined category into which I also have the dubious privilege of finding myself.
I am still none the wiser.
Best,
Alistair