Delivery capacity is a fixed number of vans and drivers per depot, and demand has roughly tripled. No amount of refreshing changes the arithmetic, but timing genuinely helps.

When slots appear

Most chains release a rolling window at a fixed hour, usually overnight, and again in small batches as existing orders are amended or cancelled. The second stream is the one most people never see.

Priority schemes are narrower than the coverage suggests, generally tied to a government list rather than a self-declaration, and they take days to apply after registering.

Click-and-collect capacity is consistently easier to book than delivery, and it is the option most shoppers forget exists.