I found this beneath its parent tree last week, in the U.K. It's something like a cherry, and the bare tree was cherry like, except for...
The fruit's flesh is mealy, like that of a hawthorn berry. The skin is solid. It's spent several months lying on the ground, so clearly unappetising to wildlife. The stone is long and ridged.

Many thanks if anyone can help

Does Walnut (Juglans regia) grow in the U.K.?
For comparison, photo of furit, nut: http://landscapeplants.oregons...

Yes we have walnuts! I think the shape of the stone is too different, and the fruit is much smaller. But the mealy flesh is somewhat similar, except for the staining juice walnuts have.
I would have paid more attention to the tree itself and looked for fallen leaves, but I thought I'd find out just from the fruit..
The long stalk and the little boss above the fruit are particularly cherry-like I thought.

Could be something a bit exotic because the owner of the garden was a very widely travelled plant collector.

[url=hxxxp://landscapeplants.oregonstate.edu/plants/davidia-involucrata]hxxxp://landscapeplants.oregon...[/url]
The dove tree!
Thanks for pointing me at that site - it has excellent search capability.

Dove Tree (Davidia involucrata)
Fruit does look like a match!

Photos here also: http://www.kew.org/science-con...