Thanks for providing sound clips.
Blues Ltd. was a very common moniker for a group, so I can't offer any clues. They could have been from anywhere. I've never heard of Nu Vue Records, label etc. Possibly self-generated by the group.
As for value, it might be super-scarce, but the true value lies in the groove - at least, that is how I decide if I'm going to buy or pay a specific price. Both tunes are decent, nothing amazing. I'd probably give them 4 out of a possible 10, might even be generous there, as both songs are not originals. Many collectors find remake versions dull and boring. The group performances on both songs are kinda lightweight.
If I wanted to sell this I'd start a bid at $19.99 on ebay with no reserve and see where it ends up.