im sure they have to provide some kind of certificate if wiping the hard drive. ask them to either return for free or provide you witha copy of the certificate. if they cant do either they're taking the piss.

if we want to get any of our IT equipment disposed of we HAVE to get an accredited company to do it and give us certificates for it. we can't take it down the dump or give it away or sell it some stupid law, dunno what.