The area doesn't look like anything would have been left after the motorway construction, however, amazingly, a brief root around in the trees just next to the motorway flyover turned up a circular, roughly flat-bottomed hollow, and more than that, one about twenty feet across, with steep banks slightly higher than the surrounding ground level, and which would, if filled with water to normal ground level, have been about knee deep. In the absence of the new drainage caused by the motorway and roads, it would probably has filled nicely from the local watertable, and, indeed, there were no signs of inlets or outflows from it (VR View looking in).
Before getting too excited, however, a few facts should be noted. Firstly, the pool is well outside the area stated for Wonder 7. Secondly, there is the remains of a large tree of at least 100 years' age in the centre of the hollow (VR View stood in centre - stump under viewer). The general decay of the tree suggests it was felled when the motorway was built. While the tree is an interesting sign that the hollow was in existance before the motorway, and was conspicuously the only thing left when everything around it was leveled, it might make having the hollow water-filled in the 1950s problematic.
In all, the site has a lot of plus points, but it's still a pretty doubtful location.