Thanks Steve and others for taking the time to look through my post, and your helpful comments and ideas.
The car is now fixed, Steve you were correct the valve timing was indeed incorrect. After careful discussion and removing an injector to ascertain actual TDC (no timing marks on engine) we discovered that when the engine was timed (and rechecked), the wrong crankshaft timing pin was used!
We did try a pressure test with the injector disconnected no double towers just a single rise in pressure but still no expansion pocket.
The engine by the way is QYWA.
Tomorrow I will take a Cam/Crank waveform for future reference and post here and to the library.