Aldi are selling XS battery chargers in store about the 16th of feb
Well worth the £12.99, don’t think that price has changed much over the years.
Had mine for years, in use today. I notice the latest ones come with a 3 year warranty.
I’ve also had one for years - mainly for little used motorcycles. Only drawback (with my version anyway) is that if the mains power is lost for any reason they become a voltmeter when re-established and drain your battery not charge it. A properly smart charger, with a tender function that takes up where it left off if the juice is interrupted, is rather more expensive.