These are manufactured by the British Royal Mint so I believe they can be spent as normal currency but the silver content far exceeds it's value as a fiat currency. The ones I pictured are 2 ounces of silver which is about £45 ($35USD) melt value and are stamped £5 so you'd take quite a loss using it as normal money.
Here's some info from APMEX website:
"The Queen's Beasts Silver and Gold bullion coin series celebrates the British Monarchy and the centuries of fascinating heraldry that has been a part of their story. Each animal of The Queen's Beasts series comes in a variety of sizes to add a range of collectible options.

At the coronation of Her Majesty The Queen, ten heraldic beasts stood guard. Plaster models were created for the occasion, symbolizing the various strands of royal ancestry brought together in a young woman about to be crowned queen. Today, The Queen's Beasts can be found at the Canadian Museum of History in Quebec, while Portland stone replicas watch over Kew Gardens in the United Kingdom.

Royal Mint Coin Designer Jody Clark has reimagined The Queen's Beasts taking form in a 2 oz .9999 fine Silver coin, a 1 oz .9999 fine Gold coin and a 1/4 oz .9999 fine Gold coin. Each of the 10 beasts will adorn the reverse of these coins. The Queen's Beasts will include the following designs:

-The Lion of England
-The Griffin of Edwards II
-The Red Dragon of Wales
-The White Greyhound of Richmond
-The Black Bull of Clarence
-The Falcon of the Plantagenets
-The Yale of Beaufort
-The White Lion Mortimer
-The White Horse of Hanover
-The Unicorn of Scotland"