I usually use Cartridge people compatible cartridges because they are cheaper than Canon genuine ones and in my previous printer I used Cartridge world refills and found them all very good. However here is a link to Amazon Canon cartridges. Amazon Canon cartridge.
I know Amazon isn't local but they do deliver quickly. When I buy on Amazon I have the goods delivered to a locker in the Co-op in Bromborough and delivery only takes two days and is free, they just email a code to open the locker when the stuff is there and you just go and pick it up.