Check out the group of plants named as alpines - most of these do well in gravelly, dryish sunny situations, as well as lavender, cistus, helianthemums.

Erinus alpinus (fairy foxgloves) will happily grow in gravel as will various of the sedums. Mecanopsis cambrica seeds all over our garden and comes up in the gravel paths too.

This may sound strange but a lot of the African amaryllis bulbs such as crinum and belladonna lily do really well in gravel sand etc because they like good drainage and you can grow them easily in the UK.

Went to Beth Chatto's garden last week. Lots and lots of one of my favourites in gravel, Verbena Bonariensis, in the dry garden. All stages ,up and flowering and about a foot tall....self seeded. The Allium Siculum, and other alliums too.

Sedum and sempervivum will also happily grow in gravel as will some of the small spreading campanulas.

Thank you