Just a small warning to people of something I spotted. On the BBC plant finder page for Lithodora diffusa 'Heavenly Blue", it says that it likes chalky and alkaline soils.
This is not the case at all. It is ericaceous and will hate that type of soil. The leaves will probably yellow from chorosis. It also says it's tender when the RHS says it's H4 hardy. Then says "Skill level : Experienced", but that it's easy to grow.
I know it says it hasn't been updated for a while, but these facts should be right in the first place. This is why on only really trust the RHS website.
(if you can't see the picture)