Having just replaced the battery on the Focus, it looks like the TT one is virtually dead. Even the CTEK charger couldn't give it enough charge to start the car. It is over 8 years old so not a bad innings.
There are a baffling array of numbers on top of the old Varta battery but I'm thinking it can't be that hard to replace the battery, can it?
Suggestions of battery to get and whether the process of replacing it is idiot-proof enough for someone like me to do would be gratefully received.