Xanthoria elegans aka Caloplaca elegans

Xanthoria elegans growing on a local Kerb Stone (in the local Monad).

Although the general appearance initially suggested Xanthoria elegans, on second thoughts, based on the appearance of the lobes giving it a perhaps crustose-placodioid appearance, we wondered, a Caloplaca?

But not a Caloplaca: it being confirmed as Xanthoria elegans.

That being said, the British Lichen Society (BLS) identify Caloplaca elegans as a synonym for Xanthoria elegans.

We understand that in the past it has been recorded as either Xanthoria elegans or Caloplaca eligans, dependent on the observer's perception. 

Interestingly, the synonym persists.