(http://www.allotments4all.co.uk/smf/gallery/9388-070715164303.jpeg)
Seemed to have a very pointed nose. There was another as well and it has a very rounded nose in comparison. Was in there for a long time, but decamped when it rained.
Sent pic to expert who says it is a common or garden frog, And there;s me thinking I had discovered something special: The pointed nosed frog.
Seems I should have taken a pic of the other rounded nosed one with the big eyeballs.