Re Princess: A cross section sketch of a nuclear installation is shown in ‘The complete encyclopedia of flight 1945-2006’
M.52 is also covered in the same book, covering much of the info above.
However, Barrie Hygate’s book “British Experimental Jet Aircraft” (1941-86) has much more detail reflecting some thorough research.
Here it is suggested that the projected failure to meet the design spec of M1.5 was a significant reason for cancellation. Wind tunnel tests indicated that supersonic flight could only be achieved in a dive, and then only 1.07 due to thrust limits.
Another concern was pilot escape. Hatch jettison, for manual bail-out was tested in a blower tunnel with limited success. The alternative of separating the complete nose capsule was complex and untried.
I also detect an underlying debate on swept wing vs straight wing supersonics. The latter, being superior at very high speed, appears again in missile development, whereas swept wings were promoted for subsequent post-war transonic research and development aircraft.