I've amassed a large amount of euro coins over the course of a few holidays, but it's annoying to take them on holiday. Will a bureau de change or bank at the airport change them for notes?
I don't know of any bank or exchange bureau that will exchange foreign coins.
Your best bet is to take the coins with you on your next trip to the Eurozone and spend them there or change them for notes when you arrive. If you still have a lot of coins left when you are due to leave, visit a store, bank, exchange bureau or even ask a local if you change them into Euro notes.
No, most places won’t exchange coins for bills but you can just buy a lot of chocolate and candy at a store in the airport that will allow you to pay in euro.
There are machines which will accept coins and give you back money, presumably in notes. I have never used them but a company which provides them is Fourex There is definitely a machine at King's Cross St Pancras underground station and their web-site has a find a kiosk link. I have no connection with the company, I just use that station occasionally.