Walter Kennedy
None of us has worried about the IFF/SSR code that was set as it can have had no bearing on the accident. As has already been stated earlier in this thread, the 'Squawk' can only have been used for conspicuity and not in connection with the 'homing' activities that you have described (at great length), as ZD576 was not fitted with the type of device that you described.
As for the radar tape, my understanding is that the earlier statement confirmed only that the aircraft headed off in the expected direction and certainly did not show the radar contact up till impact. If you think about it, this would not have been possible as at some point the aircraft radar return would have been masked by returns from the high ground beyond it. Furthermore, the crash site is just under 50 nm from Aldergrove, which would be well beyond the radar horizon anyway.