With regards to construction contracts, is there any requirement for architects to make contractors aware of clauses within the contract that may be onerous to them at the time of tender?

The architect’s primary duty is to the employer not the contractor. Should there be onerous terms in the contract then this should be brought to light at the tender stage. Contractors are bound by the terms of the contract of which they are notified at the tender stage, regardless of whether they are onerous or not.