How old is a swires roofing square?

I bought my Swires Roofing square in 1964 from Mr Swires. I was building a bungalow in Littleton Chester when he turned up at the site and introduced himself and demonstrated the roofing square that he had invented. I was so impressed with it that I bought it, and I still have it and the book of instructions.

Mr.Swires was 70 yrs. old when I met him and he was retired. He had worked as a Railway Engineer and his work was the design and setting out on site all the complicated main line, sidings and marshalling yards which was all geometry.

He lived at Clotton near Chester which was near where I was working so he dropped in several times, I found him to be a fascinating character,every conversation with him was an education he was like a breath of fresh air.

I paid £25 for the Roofing Square and although I never made good use of it later I kept it for its inerest value.