with all that maltiness swimming around aroma hops are really not for porters.
you could make a tea from fuggle as the grassy notes work well with the nutty earthy dark malts, or maybe an East goldings more subtle but not distracting from the porter.
But if you are looking to alter the porter significantly try some new world hops and see where the rabbit hole leads you.
A London Porter can really use fuggles or goldings (I tend to use fuggles) but all up front really at the start of the boil. Anywhere between 100 and 150g in a 23 ltr brew
Cheers for the advice all, think I'll try the fuggles as they've got some in the local HB shop,
just one more quick one - what's the difference between pure hops and hop pellets and can
you use both in the same way (hop teas and dry hopping for instance)?