Took the car out for a photoshoot last week and left her lights and fogs on for not more than 7-10 minutes but with engine off. Couldn't start her after that.

The wife came with croc-leads and we jump started her but I only drove her home which took two minutes. Next day... dead as a nail.

A couple days later, I jump started her again and this time drover her around for 20-25 minutes and gave her a couple of hard bursts of power and speed in the middle. Turned her engine off and on right after okay but now (two days later) she's dead again.

No, the interior light is not left on by the way. I can't think of any other interior settings etc. that would cause a bleed of the charge so what does this mean?

Oh, and she turns over ever so slightly slower in the increasingly colder weather these mornings as well (but with no coughing). Perhaps one or two more "rer-rer-rers" if you know what I mean but they are (a little) slower than they were earlier this summer when it was warmer.

I'm happy to replace the battery but don't want to if unnecessary. Has anyone got advice about how to determine the problem?

Cheers!