Gillingham, refueller just outside marina, 108p/l on Sunday, (but I think it gets a couple of pence cheaper at 200l). If you have cans and only need a bit there is a cheapo garage 100yds to North of Rochester Bridge, warf on North side just past bridge dries but bottom is clean and plenty of water three hours either side of high tide. Also MDL Chatham but only inside the marina. Mobo readers might be able to advise.