You wouldn’t have had that many.
One advantage of working in a bingo club is the large amount of cash of all denominations. A customer once asked me to change £200 in £1 coins to "tens". So I gave her £200 in 10ps. Just for a laugh.
We accept £50 notes, but they get checked 6 ways from Sunday.
It isn't a matter of a dodgy customer, either. Many fake notes are passed innocently by people who don't know how to spot a fake and have had one or two passed on to them.
Suprisingly, the most common fake money we see is £1 coins. Stacks of those. It seems pointless, as they never go in any machines and anyone with any knowledge can immediately spot that they're fake. The gold colour scratches off, they are often the wrong colour anyway, the weight is usually wrong (so they sound wrong when dropped)...obvious fakes.
The worst time we had was when someone made a batch of fake £20s that were accepted by the model of change machine used in many of our clubs. Insert fake £20, get 20 real £1 coins, repeat.