Can standing orders and direct debits be set up on my old account, once I switch?

Yes, if the old account remains open and allows it.

You can set up new standing orders and direct debits on the old bank account after the existing standing orders and direct debits have switched to Bank of Ireland.

Some companies may not let you pay by direct debit for two months after a previous direct debit to them was switched to a new bank. If this is the case, talk to the relevant company.