There should be trollies at all the terminals, but they tend to get dispersed and it can be some time before they get returned to where they are meant to be. If there are non obvious, then if someone can wait with your luggage the others should be able to track one down quite quickly. There are some porters but they are not so visible as in the U.S. And rarely out offering their services.
We are from the UK and have never used a porter in a UK airport, but use them all the time in the USA because they are just there!