mymemory have a 2 for £22 deal on Anker Powercore 10400mAh powerbanks with free UK delivery.
Two charging ports & quick charge.
Seem to be around same price for one on amazon.
You will likely need to use AP as I've had issues getting batteries shipped before.
EDIT: Seems they're available on the .ie site as well (2 for €27.50) with free delivery, assuming they'll ship batteries here.