For the information of anyone who has a UBCD3600XLT and a BCD536HP imported from the US, I have discovered that the UBCD3600XLT and the BCD536HP although they ostensibly use the same data files, do not use the same frequencies for "Band Defaults".
These are used the frequencies in the UBCD3600XLT (Who set these up, and for what country is not clear as they do not all match UK bands)
25
30
54
76
80
83
84
87.3
88.0
108.0
137
138
144
146
156
158
160.6
162
162.6
174
216
225
400
406
440
450
466
470
806
894
1240
BCD536HP: (Presumably bands in the US)
25
26.9
27.4
28.0
29.7
50.0
54.0
72.0
76.0
88.0
108
137
144
148.0
150.8
162.0
174.0
216.0
225.0
380.0
400.0
406.0
420.0
450.0
470.0
758.0
788.0
806.0
849.0
894.0
1240.0
The key point is that although both have 31 bands, significant bands are not the same ID number, the VHF Airband in 10 in the UBCD3600XLT, but 11 in the BCD536HP.
So if you try and use the same data in both, one of them is going to be wrong.
Frustrating that Uniden does not make the frequencies user-programmable — which would solve the problem.