For reference, my commute is 6 miles and takes about 11 mins each way and I have no need of routinely topping up the charge. It's only if it is regularly being used on short journeys you might need to.

I went with the Yuasa YBX7096, but anything from Varta or Borsch should also be just as good.

https://www.tayna.co.uk/car-batteries/types/096-efb/

So its not harmful, right?

First time-pushing the rear fog light switch- the battery icon flashed on dash, but the auto start stop didnt work,

Second time, today, pushing the front fog light switch- the battery icon didnt flash, but the auto start stop worked again.

1 minute ago, Bol said:

So its not harmful, right?

First time-pushing the rear fog light switch- the battery icon flashed on dash, but the auto start stop didnt work,

Second time, today, pushing the front fog light switch- the battery icon didnt flash, but the auto start stop worked again.

Because the car thinks the battery is newer than it is.

You shouldn't perform the BMS reset unless fitting a new battery.

All you've done is make the car think you've fitted a brand new battery.

If stop start doesn't work, you either need to charge your existing battery, replace the battery if the old one is not holding a good charge, or more ideally just forget about it and get on with your day.

1 hour ago, alexp999 said:

I went with the Yuasa YBX7096

Likewise, and also set the SOC on my Focus Mk4 to 95% instead of the factory default of 80%.

This was the condition of my battery yesterday after 2 weeks of many short, stop and start journeys.