These are what I call good old fashioned speakers. Big box, big bass driver -
Google-UK - Image Search - Wharfedale E70
With any vintage speaker, it gets down to the type of surrounds, and the condition of the cones.
Foam sorrounds, that soft ring that attaches the cone to the frame, typically do not last long before they start to crumble. Though Butyl Rubber surrounds can last for decades.
Certain cone material, especially paper cones can deteriorate if exposed to humidity and moisture. Though again it varies from speaker to speaker. I've go bass drivers purchased around 1980 and the cone (paper) and surround (rubber) are still in pristine condition.
As to the specific speakers themselves, I confess little knowledge, but following the image search above can probably lead you to more information on the speakers.
I would expect them to be good, though not necessarily great.
As an example, check out this other forum where the E70 are being discussed. Apparently, you get some serious bass from these speakers, and when they turn up on Ebay, the bidding tends to be hot -
Imminent Hi-Fi Gas - Page 2 - MusicRadar Forum
See Post #17.
Also, this should give you some sense of their current value -
Ebay-UK - HiFi Speakers - Floorstanding speakers - Wharfedale E70 (£525)
Steve/bluewizard