Battery for Gtech Multi cleaner (Prestwood HP16)

This is a long shot but does anyone have a battery for a Gtech Multi hand held cleaner please. We were given a virtually new Gtech Multi by an elderly aunt. It came with two batteries but despite supposedly charging them (there are no indicator lights to show status) neither will make the unit work. It could be that they have passed their use by date so wondered if anyone had a battery known to be OK they didn't want that was going spare please. Many thanks for reading all this! Julie