Pye dual standard TV set in 1960.

[Synchrodyne]

But weren't the frequency allocations for the eight UK Band 3 channels already decided upon by 1953?

Certainly, the ITU Stockholm 1952 Meeting (ST52) outcome included a full set of Band III allocations for the UK.  However, these were provisional only, as noted in this excerpt from Wireless World 1952 October:

   

I haven’t checked, but I should think that this list, from WW 1953 June, was taken from the ST52 Final Acts:

   

Probably quite a few of the ST52 listings were provisional or later changed anyway.  For example, there was an allocation for French TV channel F3, which was never in fact used.  (My take on this is that channel F3 was probably abandoned to avoid the need for “double-ended” IF strips in TV receivers.  With a vision-low IF strip, channels F2 and F4 were still usable, so that was the “lesser cost” pathway taken, although a longer-term consequence, almost certainly unforeseen at the time, was the eventual need for System L’ in Band I, with inverted channels.)


Cheers,

Steve