On the subject of knapping, Kingsdown, like other places on the chalk, has many examples of the use of flint in construction. The older part of Dial Cottage, above, is a good example of a flint-faced building, alternating with rows of brick.
The wall around the church uses roughly-knapped flints as filling between sandstone. The church itself, being relatively recent, does not use flint, in contrast to the older churches in surrounding villages.
The wall of the 'big house' uses knapped flint and brick to a pleasing decorative effect, similar to that of 'Wayside' below, which is much older.
Returning to the etymology of 'Knapweed', the word 'knap' was used to mean 'to take' or 'to steal', and to be 'knapped' meant to be pregnant, as did 'Mr Knap's been there'. Your knapper could mean your head, while your knappers (confusingly) are your knees.
I expect that the word 'flint-knapping' comes from the sound of chipping away at a stone to give it the right shape....knap, knap, knap....but that's only my guess.
On another matter, there were over a hundred Marbled Whites on the beach between South Road and the rifle range today (the first and maybe last day of summer?), with smaller numbers of other species including my first Gatekeeper and Clouded Yellow of the year.