Error reply.

You would have to ask Ebay that - I don't know if there are general UK restrictions, but Ebay do not allow the sale at all of used e-bike batteries.  I would assume it is due to the fire safety risk.  Private sellers can't sell e-bikes at all and business sellers have to meet certain standards to sell new e-bikes.

https://www.ebay.co.uk/help/policies/prohibited-restricted-items/products-eligibility-requirements-p...

People were selling second hand used e bikes and some then caused fires.

Perhaps one too many of these occurred , and the general history of these fire hazard items, so from a purely safety reason only registered sellers selling new e bikes which have all the required documentation/  guarantees  are able to sell them now on eBay.

@farr.david2012 

Only authorized Business dealers are allowed to list eBikes /accessories etc. on eBay due to safety concerns.