Time Out says
Posted: Thu Oct 27 2011
Marylebone's classiest grocer's shop, (and they have a Waitrose!) Natural Kitchen sells an excellent standard of fresh produce, sourced as locally as possible to the airy, rustic premises. It's worth a trip for the butchery alone - brought in three times a week from a Kentish farm - though (unsurprisingly considering the catchment area here), it'll cost you.
Natural Kitchen 77-78 Marylebone High Street