Money/cash bag Quantities

The Undated 20p thing inspired me to count the change in Percival my piggy bank and i have about £40.

I don't have any cash bags from the bank.
What are the quantities of each denomination you have to have in the bag?

X x20p
X x2p etc etc

so that i can separate them all up for when i go to the bank and get some bags rather than just chucking it back in the pig!