Mowbrays Slap

This is my favourite street name in my home village; in fact, perhaps anywhere! It tickles my Dad pink every time he sees it, but I can't find out what it means. "Slap" I think, means small street which is apt as it is a very small lane. Fredaquilter: any ideas? I love the carvings in the stonework which I notice almost every time I walk or drive past.