Very difficult, I think. "Civilisation rises, lions fall" is the main theme of my favourite book, and it applies equally to large predators in the British Isles.
I think the way to have surviving populations of wolves (bears are very, very difficult to imagine) with a fairly late POD is to somehow avoid the centralisation of Ireland- perhaps have the island partitioned between various small states supported by England, Scotland, and France. The Irish population remains low and backward, and areas of wilderness large enough for wolves to survive remain more or less intact.
Alternatively, you could have the wolf declared a protected animal of kings by someone or other, and make it a capital offence to kill wolves- wolf hunting would be restricted to the royal family. Given the negative connotations wolves have, though, I think that again this is difficult.