My car came with a sealant kit instead of a spare. What do I do if I get a flat?

Do not use the sealant if you are somewhere safe enough to wait, because it makes a permanent repair much harder and often turns a repairable tyre into a replacement. Sealant is also no use at all on a sidewall split or a blowout, which is what most drivers actually get on the A562 and the bridge approaches. Ring the callout line instead, tell us the size off the sidewall and we will come with the tyre on board. If you have already used the kit, say so when you ring so we can bring a replacement rather than plan for a puncture repair.