You're quite correct. ITV started in 1955, but down Zum'zett way it didn't come on air until 1958 when TWW started. Our old 9" Bush was Band 1 fixed frequency, without the 'Band Converter' which facilitated ITV reception on Band 3. So my father upgraded to a secondhand Peto-Scott. BBC1 on Channel 5 and TWW on Channel 10. Then in 1961 came Westward TV on Channel 9, but the chap who came to fit the crystals put the wrong one in, so we briefly had Westward picture and TWW sound!
It all seems so dreadfully primitive now - the attractions of Airfix, Frog, Revell, Aurora and Lindberg were much more interesting!!