The leaves are small and rounded, with rough upper surfaces, so this should be the English Elm, Ulmus procera, the commonest clone in England. The blobs on the upper leaf surfaces are caused by the Eriophyid mite, Aceria ulmicola, (Nalepa) (=Aculus = Eriophyes ulmi = campestricola) which is supposed to only infest English Elm, according to some but not all authorities.
As with most elms, the stems are often heavily winged with corky outgrowths:
The suckering trees on the access trail are repeatedly attacked by the bark beetle and continually re-infected with the Dutch Elm Disease fungus, causing them to die-back again and again.
