There are exemptions but I suggest more caution, or at least from the supplier.
Para 4.9: "VAT relief doesn?t apply to the separate supply of general use items such as standard batteries, even if these were purchased to be used within an item which is eligible for VAT relief such as a mobility scooter."
and Para 5.5: "............. a general purpose battery may be zero rated when supplied as part of a wider service of repair and maintenance of a zero-rated mobility scooter."
That suggests the supply of a standard battery should not be zero rate, but where the battery is fitted as part of a overall maintenance or service, then that maintenance or service can be zero rated.
In that respect David is correct. The supplier of your batteries could easily be on the wrong end of a VAT bill from HMRC for non payment of VAT and a further penalty of 100% of the unpaid VAT.
If you're in doubt, leave the name of your zero rated battery supplier here and see if a few months down the line they still provide zero rated batteries.