David-Paul Sip
To send copies of the instruments and not return the ORIGINAL instruments is not only a UNILATERAL (to use your words) decision to keep them against the wishes of their owner John Trew but a UNILATERAL decision to not use them for their intended purpose.
Since HQ is CHOOSING not to return this property then they have been given NOTICE of the cost associated with doing this. This is not "silent acquiescence". It is an ACTIVE choice to do or not do something. They either return the property at no cost, or do not and pay the disclosed cost.
How is this "Meads vs. Meads" or some Free-Dumb misconception? Since HQ can simply return the property then this IS binding if they do not return it.
To not return the instruments means HQ has ACCEPTED them for their intended purpose which means the debt must be DISCHARGED. This represents a contract and these are the terms and conditions which became BINDING with ACCEPTANCE of these Bills of Exchange.
So Capitaine Pete is giving HQ fair warning by disclosing what the charge will be if his property is not returned since they have not zeroed the account. Pete does not wish to sell these instruments. He is looking ONLY to discharge the debt of the PERSON. If the instruments are not being used for the purpose intended by the SOLE AUTHORIZED ADMINISTRATOR then they are to be returned. Very simple. These are the terms and conditions.