In predecimal coinage notation in the UK, the symbol should be the solidus symbol, because the word "solidus" comes from the Latin name of a coin. Pounds shillings and pence were also notated with £, s, and d. Which came from the Roman silver coinage denominations librae, solidi (plural of solidus), and denarii (plural of denarius).
The solidus wasn't used as a divider. It actually stands for shillings/solidi
So you would never write £1/5/- It would be written as £1-5/-
Pennies were added after the solidus, for example £1-5/9d, sometimes with or without the d.
It could also be written as £1-5s-9d, sometimes with a centre dot as separators instead of a hyphen, or a long dash instead of a hyphen. Sometimes just a space separated pounds from shillings. For example £1 5/-
It's also interesting to note that instead of £1-5/- people would often convert it to shillings when writing it - for example 25/- or 25s.
My source: An old person (82) who I just asked. Also if you look at some old newspaper adverts you will see how they actually did it. Sometimes the solidus was something more akin to a long apostrophe. There's an example here.
