My name is ***** ***** I would be happy to help with these.
I believe Mappin & Webb marketed these pretty glass lined footed cups as sundae or sorbet dishes.
If they say "Triple Deposit" then they are silverplate rather than sterling silver, so not as valuable as sterling, sadly.
From similar ones that Mappin & Webb made in solid silver (that are date marked) we know they date to the 1950s, so not especially old by English silverware standards.
As for value, Mappin & Webb are one of the preeminent names in English silver so they do have some value. Your footed and pierced silverplate cups with glass liners would have a retail value (if you saw them for sale in an antique store, say) of about $300 for the set of six.
This is also the the replacement value for insurance purposes.
Expect to net 30% - 40% of this if you were to sell at auction or on line (eBay etc).
I do hope this helps!
Please let me know if you'd like me to explain or expand on any of the above, I would be glad to.