Thanks to a bit of local help from a photographer I bumped into, I was able to track down
Yarrow Broomrape (
Orobanche purpurea) on the cliffs at Sheringham.

(
Yarrow Broomrape, Orobanche purpurea)
Sand Catchfly (
Silene conica) was a very welcome find here, too, since I'd missed this supposedly frequent plant of Breckland a week or so earlier

(
Sand Catchfly, Silene conica)
There were also a few good escapes here;
Garden Lavender (
Lavandula x intermedia), seemingly well-established (it's listed on an information board, at least...

) and
Maltese-cross (
Lychnis chalcedonica), competing with the long grass.

(
Garden Lavender, Lavandula x intermedia)

(
Maltese-cross, Lychnis chalcedonica)