You will find many taxis will take cards and also, but less welcome is cash these days. A tip paid by cash would probably be more welcome. For a journey to tilbury you would probably be best to book in advance, some of these would also take advance payments. You can find these online (see other responses) or they may be cards or recommendations in the hotel. Although quite basic my experience is that premier inns will always try to help. If you call for a taxi straightaway it is likely to be much more expensive.