"Trying to start a no dig garden in some heavily compacted, organic-poor, heavy clay soil is going to lead to extreme disappointment".
For sure. In Dowdings method you put a quite thick layer of compost on top of the existing soil. You then top up the compost every year.
Raised planters can help too
Oh yeah, just top up the compost every year. Where are you getting that compost from? Wood chips you say? You'd have to denude ten acres of forest to make enough compost to Dowding one acre of field.
He's a soil vampire, sucking in fertility from somewhere else to feed his own garden.