In article , Janet Sanderson
writes
I wondered if it was a mulberry, it has a leaf a bit like a lime. The
fruit does look delicious, and its tempting to go scrumping.
I may have to take pictures

The upper surface of the leaves of Morus nigra has a sandpaper-like
texture (to the touch); this distinguishes from all the limes with which
I am familiar. (The upper surface of the leaves of T. platyphyllos is
woolly to the touch; in other limes it is glabrous.) Hillier says that
it is downy below.

The leaves of Morus nigra are also typically 3-nerved at the base,
whereas limes are 5- or more- nerved, and sometimes asymmetrically
nerved.

Whatever it is (and mulberry is what springs to mind from your
description) the fruit eliminates many other genera containing species
with cordate, ovate, acute or acuminate leaves, such as Tilia, Ulmus,
Corylus, Populus, Alnus, Cercidophyllum or Davidia.
--
Stewart Robert Hinsley
http://www.meden.demon.co.uk/Malvace...a/Britain.html