Len could not have been in the david hotel bombing because the king david hotel is in jerusalem and he was stationed in haifa. The distance between jerusalem and haifa is more than 100 km, and in those days it would have taken about 2.5 hours or even more to travel between the two cities.
sharewhile we are at it, the king david hotel bombing was after the "black sabbath", when british troops confiscated weapons. the confiscation was at june 29th, 1946 and the bombing at july 22nd, 1946.
and more so, he could not been in dir yasin, which is close to jerusalem. the jumps between haifa and jerusalem are just impossible and make the whole thing unreliable.