ID yellow fruit?

That looks very like the Cherry Plum also known as Myrobalan or Mirabelle. The leaves don't look plum enough for me.

Have a look at this photo:

http://wwwdelivery.superstock.com/WI/223/1606/PreviewComp/SuperStock_1606-52343.jpg

Hi Fratal... leaves definitely do not look plum like but fruit does look like Mirabelle... MBD is this a 'stone' fruit?

Far too late for cherry plums.. but not sure what this is.

Hi Fractal. I couldn't follow the link but looked up Mirabelle plums and they do look similar. However, the ones I snapped lack any pinky blush or that powdery-looking skin that some of the pics portray. Also, the fruits are on longish stems.
Moongrower, yes they are stone fruits - I've eaten one.

They look like wild greengages....though the leaf is a bit suspect. Years ago we had similar fruits growing in our wild hedge.