Phil Pugliese asked:

>     Well then that would mean that there was no coin 'tween the new 10p & the new 50p?
Correct. Just after decimalization the coins were 1/2p, 1p, 2p, 2-1/2p (old sixpence),
5p (old shilling), 10p (old florin), and 50p. The 50p coin had come in in 1969, replacing
the old ten-shilling note. The 20p coin came in in 1982, and the 1-pound coin the year
later. The half-crown (old 2s6d), which would have been 12-1/2p, had been withdrawn in 1969,
and the crown (old 5s) in 1965.

Over the centuries there were many different coins.
See eg https://en.wikipedia.org/wiki/List_of_British_banknotes_and_coins

IMTU (just to try and drag this back to some sort of relevance) I peg the credit at
about $2 (for no particularly good reason other than convenience). I still have
physical money, in the form of small-denomination coins (centi- and even milli-credits),
but it's not widely used, except on special occasions.

Jonathan