Remember these?

Was clearing out some old school worksheets etc that I'd kept, thinking I'd use them sometime (never) when I came across this little box of letters.
They weren't used when I started teaching as I had to write " words" that occurred in the reading books on little pieces of card for the children.
They kept them in Golden Virginia tobacco tins that I'd got from my dad who rolled his own cigarettes. Would be frowned upon today!
As you can see there are two letters missing.
"Can I have a "P" please Bob?
Honestly,there are no letter Ps or Os!