I disabled the start stop on my Fabia Mk3 by taking the connection off the -ve terminal on the battery. Is it the same on the Octavia, and has the same effect, i.e. the s/s no longer works and the battery charges fully?

Yes, but what you don't want to do with Stop start batteries is overcharge them. An AGM battery dries out over time and shortens the life of it when overcharged. Start Stop batteries don't need a full charge as they operate below that level as part of the battery management cycle, particularly AGM's for best performance long term. Plus its part of the emissions thing to not waste energy running the alternator when its not needed.

1 hour ago, BigEjit said:

Yes, but what you don't want to do with Stop start batteries is overcharge them. An AGM battery dries out over time and shortens the life of it when overcharged. Start Stop batteries don't need a full charge as they operate below that level as part of the battery management cycle, particularly AGM's for best performance long term. Plus its part of the emissions thing to not waste energy running the alternator when its not needed.

It's an EFB battery, does that change the scenario?

 

EFB is a flooded type so there is a lot more fluid available compared to AGM,  but the same principles apply. By overcharging the battery it splits the water content out into hydrogen and oxygen gas when it can’t handle the extra charge and is largely contained in the battery. If it over pressures, you lose some of this gas and therefore some of the water content.

 

Do this too frequently and you slowly increase the acid density as the water level reduces and slightly increases the internal decay process. You can’t detect this from outside the battery other than a slightly eggy smell and it usually ends in early life failure. 
 

if you lose too much water too quickly and the battery is still operational, it is possible to create a scenario where a spark is able to bridge between plates In the airspace igniting the gas in the casing, blowing the lid off the battery. I have yet to see this on a car because the battery management systems keeps things in check but I have seen it on buses and static engine applications using huge commercial truck batteries. It gets messy.