My no-dig allotment is at the Pimp Hall Allotment site in Chingford, London.
I've built up a reasonably useable compost top layer over the last 5 years, overlying a pan of solid London clay, which the diggers on neighbouring allotments have constant difficulty with! We're lucky that since the local authority ceased delivering "brown bin" compost a couple of years back we've had regular supplies of leafy wood chippings from their tree contractor. This, plus occasional deliveries of horse muck forms the basis of my three compost heaps. The plot is situated next to a recently renovated pond which has existed as a watering hole for cattle since the 16th century.
We have regular visits from local primary school children whom I try to indoctrinate with descriptions of the role of fungi and bacteria; they do appreciate the vital role of poo.
The photo shows surviving Brussel Sprouts.