I've just completed a 1500-mile roadtrip to Scotland and back in my little Sirion. Quite seriously impressed with how well it did. However, the fuel filler neck is a problem. It's quite seriously rotten! Fuel leaks out when the tank is absolutely full. Can you get a replacement? Is it hard to fit?

This may not be connected but I'm worried that if fuel can get out, water can get in. Towards the end of yesterday's 560-mile epic, the car began to lose power on left-hand bends. Felt very much like fuel starvation. I'll change the fuel filter to start with, as I haven't done that yet (where is it?) but I'm a bit confused as to what the problem might be. The fuel tank was holding just under a half of a tank.