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](https://c8.alamy.com/comp/KM55DE/1950s-old-vintage-original-advert-british-magazine-print-advertisement-KM55DE.jpg).

Another [example here](https://aipetcher.files.wordpress.com/2011/12/gaberdine-raincoat-1965.jpg) for a higher priced item priced in shillings.  In this case 79/-, instead of £3 19/-

Another interesting thing to note is that very high priced items such as a television set were often priced in guineas - abbreviated GNS. A guinea was £1 1/-. So [in this example](http://www.retrofair.co.uk/uploads/8/7/5/9/8759988/4778744_orig.jpg) 78GNS would be equivalent to £78 and 78 shillings, or £81 18/-

All I can say is thank God for decimalisation. Imagine having to work this all out in your head!