I haven't been bothering with the trickle charge recently because I've been doing a short 4 mile or so trip 3 or 4 times a week recently. I know that this is not enough not fully charge what the car takes out on engine start, but I got lazy with the constant plumbing.
Low and behold - low battery warning yesterday afternoon. I left it on the CTEK charger overnight and it too was only at stage 4 this morning.
Just goes to show how much care these things need when you're not using them constantly.
I'll be rotating tyres soon