I dont know about the Twin Pioneers but certainly the single engined variety were shipped to the Far East by sea. When I was at RAF Seletar, 1961 to 1964 I was in the 17th Singapore Scout Group and we were gifted a "Pioneer Box" by the RAF to use as a secondary storage room and scout hut. It was basically a large box painted in a grey colour and I clearly remember it still had the shipping details stencilled on the side. I would strongly suspect that the Twins were also shipped this way as well.
Not all of them, hence my comment. As a young spotter, I remember seeing two of them one day when I rounded the terminal building on a wet afternoon at Speke. Photo in post below:
Perhaps, as a result of the early flights, it was decided it was better to crate them and send them by sea.