Euros from Heathrow ATMs?
 

Do any ATMs at Heathrow (terminals 1 and 4) give you euros?

The currency of the UK is the British pound, so that's what the ATMs will dispense. If you are just having a layover at LHR and going on to a country that uses €s, you can get those at the airport of your final destination.

ATMs I saw did pounds, however there is a couple of currency stands in the hall with the food etc. for ongoing passengers. Just be savy and more or less know the going rate to see if that works for you

£ only. Wait until you get to your destination airport to get euros from THOSE atms. If you absolutely need to have euros before you land, there are a few exchange counters around. Best rate will be from the ATMs at the destination airport.

no, but it would be a very good idea.