i used to use fleece covers on my super pee-r! she woke up dry every morning, much cheaper option that splurging on night nappies. defeintly worth a shot. i bought mine from squeaky cheeks of the wahmnaps site.
we've got maz's night and BBH night, both have never leaked.
BBH dont have any in stock atm, but u can get them on ebay for the same price.
Good luck hun