A warning light came on in the car, one that can sometimes indicate something expensive. I took it to a local garage and it looks like the issue is the fuel flow, likely caused by a faulty sensor so (hopefully) nowhere near as expensive as it might have been.
It's okay to drive but I've got to take it back on Wednesday for a full diagnostic.
It's the same light that comes on if the catalytic converter is faulty which is very expensive to replace so I'm glad it's not that.