Why does your bank not accept the Five Pound coin?

Answer 1

The Royal Mint advises -

The £5 crown piece is issued to commemorate special occasions of national importance. These coins are not intended to be a permanent feature of the United Kingdom circulation coinage, rather they are intended as souvenirs.

In its present form, the cupro-nickel crown has a face value of £5 it was increased to this value from 25p in 1990. This increase gives the coin a value consistent with its weight and size in relation to present range of coins.

Each new crown issue is authorised by Royal Proclamation, as required by the Coinage Act of 1971. A crown therefore has legal tender status, but since it is not a circulation coin, most retailers will refuse to accept it. In recognition, however, that some people may wish to exchange a crown piece given or purchased as a souvenir, post offices have agreed to accept crowns in exchange for goods and services.