Cotoneaster horizontalis, here (as often) seen growing against a wall in a verticalis manner. The other leaves you can see are privet.
Stace records 68 species of Cotoneaster, mostly from China or the Himalayas, that are sometimes found in the wild in the UK. This species, also known as Wall Cotoneaster, is the commonest and one of the easiest to identify, because of the "herringbone" branching.
(Just one of them, C. cambricus, the almost-legendary Wild Cotoneaster, is native and indeed endemic - discovered in 1793 on the Great Orme in N. Wales but now reduced to six plants, a genetically distinct offshoot of the widespread Eastern European C. integerrimus. Wikipedia has good info and links.)