George VI & Elizabeth II Shillings & Florins

A few of the G6 coins are 50% silver so have some bullion value.
The rest were minted in millions.

I agree that some of these coins are undervalued. I expect that all dates from 1954 to 1962 are quite scarce in UNC as not many would have been put aside at the time of issue. The later dates are probably plentiful in UNC as lots were put away at the time. When sorting through bags of 5p/shillings in the 1990s I found fewer 1965 Scottish shillings than 1961s, but all catalogues show the 1961 as more valuable. Dealers and collectors recognised the 1965 as a scarce coin at the time of issue, and saved large numbers of them.

I remember looking through some old copies of the now-defunct COIN MONTHLY magazine a few years ago and noticing that several Elizabeth II cupro-nickel coins were selling for less in 1988 than in 1968. Many modern British coins spiked in value in 1967-71 when lots of collectors were building sets of pre-decimal coins prior to decimalisation.

I can't think of anything that would make Elizabeth II cupro-nickel coins go up in value - there doesn't seem to be any increase in the number of collectors, and most people prefer earlier silver or the more recent decimal issues.