Signatories to a cheque

If the arrangement requries both the holders to sign the cheque then both should sign it.  this is done to prevent any misuse.  this practise is followed in big organizations where the transactions are numerous

if the arrangement requries any one of the holder to sign then any one of them can sign.  This is in case of a partnership firm, wehre any of the partner can sigh the cheques, provided it is not stated otherwise in the p'ship deed.

Thank you. But is there any onus on the second signatory that the details provided and signed by the first signatory is accurate?

As a matter of prudence Yes.  however care should be taken by the person preparing the cheque that all the details such as the Name of the party, amount & the most improtant date is correctly entered.