It's Santolina. It grows to about 1.05m high and 0.5m wide. It loves a sunny spot and is pretty hardy though can be short lived. Trim it back after flowering to keep the shrub dense.

I'm thinking Golden Alyssum (Aurinia saxatilis).

It's not golden alyssum it could be a Santolina but you didn't give a second name so I can't find it as it's a largish species. I looked again at the entire Santolina photos on Google and couldn't find anything similar ...Unfortunately my photo is not clear enough to see the leaves that were exactly like a euphorbia so maybe it is come kind of unusual euphorbia with tiny flowers

Can you get a close-up of the flowers, Alastair?

Sorry but that's the only one pic I had...I contacted titsey place but I'm sure it must be a silver grey euphorbia although you can't see it the leaves were defiantly euphorbia like

I asked at special plants but no one could I.d it. There..