Hi Lee,
I see from previous posts that ProChem leather cleaner has been tried and tested by people in this group and you can purchase that from our hosts at Express Cleaning.
I have just purchased some leather cleaning products from LTT who are on this group and will be trying them tomorrow on a Beemer & an old Austin Healey.
I'll let you know how it goes.
P.S. I would give the battery acid a miss, (and there's NO CHARGE for that information)
Les