Hello Richard, welcome to no dig.
You need to decide whether you want high yields and cropping throughout the year, or lower yields and just one crop of say onions, with nothing planted after, such as fennel, chicories, beetroot etc.
For intense and continuous cropping, your size allotment (it’s 1/17.5 of an acre) can use up to three tons annually.
For less intense cropping, and perhaps more weeding, one or two tons.
Vegetables demand high fertility, whether one digs or not. The amount of compost/added organic matter you need is slightly less in no dig than when soil is dug, because no carbon is lost to atmosphere in the cultivation process.
