Created my account (finally after lurking for years!) to reply to this topic, as I've finally got a battery I am happy with.
I don't drive for work so I have never used my 86 daily, I started off with the stock battery like everyone and it was appalling. Dead after a week, 10 days at most of no driving, within the first month of ownership from brand new. My dealership happily changed it for the 60 Ah Toyota branded one, which was considerably better, but still less than ideal. After two weeks of sitting on the driveway it was certainly less keen to turn over than when fresh.
Come early 2020 and covid times, I didn't drive at all for 6 weeks or so back in the spring. While only a little over 2 years old, the Toyota 60Ah was completely killed from this lack of use. When lockdown #1 lifted I couldn't even start the car with a mains booster, the most I could do was activate the alarm in my driveway lol.
So after some research on both this forum and the other place, I ended up with the Yuasa HSB 096 Yuasa HSB 072 from Halfords (I think this is the model, please ask me to take/post a pic and confirm if you're not sure and about to go and buy!). 80 Ah for ~£115, and I couldn't be happier! After 3 weeks of idle it still leaps in to life at first ask, shows near 12V on the meter if I check before starting, etc. - My starting fail / flat battery anxiety of previous years is now a thing of the past.
Up to you if that kind of expense is "reasonable", but I certainly consider my previously very annoying battery drain completely solved for now. No telling how long this battery will last, but it's been maybe 6 months now of very light car use and it's still perfect!
