Could be around 1970. My dad had some Gordon spanners among his kit. They are a reputable brand, long gone I believe. The slip jaw waterpump pliers were used all the time.
The jaws are a little bulky but I think these will be strong and durable. Good save !
I've got an ancient Gordon socket set, from long before the days of metric, but excellent tools. Sadly, I fear the ones you have would only sell for a fraction of their "real" value.
Good, solid spanners. Not the same quality as Britool or King ****, but very workmanlike. As Bod says, put them on eBay and see. I'd start them at £19.99.