This is actually not a Santander bike but a Lime bike - it has been standing at the corner of Leamington Close and Priory Road since 05 Dec and I'm not sure anyone is actually using it. The reference number on the back mudguard is ZDP021.
Thank you for taking the time to report this to us. It is much appreciated. Our team had investigated this for you and found that this is not owned by Transport for London. This means that we are unable to resolve the issue. You may wish to contact the owner to report your issue. Should you need anything else, or have any questions please contact our customer services team on 0343 222 1234