As mentioned previously, when talking about dust jackets, I referred to “The Fountain Of Life” by A G Prys-Jones. I have three versions of this, all dated 1949, but one is the hardback version and two paperback versions. One of the paperback versions is the same size any other PAN paperback, 112mm by 178mm, but the other is what I would call over-sized being 117mm by 182mm and having a dust jacket and a plain cover inside. It was only while showing someone these they said wasn’t the larger paperback the same size as the hardbacks text pages? On measuring them I found they were right so all I can think is that PAN had a lot of the hardback sized pages on which they just put a dust jacket, looking the same as the ‘normal’ paperback version, making a paperback rather than the red cloth hardback.