You are going back a long time here.
The E designation means that they are from 1960. They are old studio monitors.
These come from a Time when Celestion was a UK company.
These would be up against Tannoy, and WB Stentorian and firms like that in the UK. In the US Altec, JBL, West:ake EV would have been competitors.
I suspect that these speakers are 16 ohm and not that useful in this age.
Although the driver is large, efficiency was at a premium, so the speakers will not play that low. The bass driver will driven way into break up range, so the mid range will not be all that smooth.
These speakers are more of a collectors item and an example of the type of commercial sound of that era.