Lie down, close your eyes - and listen to this superb realization of the sumptuous slow movement from Vivaldi's the Four Seasons, in the version I bought with pocket money as a teenager.
The performer of the harpsichord "improvisation" is unlisted, but was probably Leslie Pearson; the Orchestra is the Virtuosi of England conducted by Arthur Davison.
The Virtuosi of England was a "scratch orchestra" organized for recording on the legendary (to me!) Classics for Pleasure label (whose recordings constituted about 90% of my schooldays record collection); composed of some of the excellent soloists moonlighting from the major London Orchestras of the day.