Young people are being urged to submit updated versions of the independence document for a new project.
More than 1000 slots have already been pre-booked in the first few days of tickets being made available online.
Heritage charity appeals for groups to contact them if they can use the treats after hunts cancelled.
It comes after the heritage body warned 429 of its workers face being made redundant due to Covid-19.
The conservation charity said it is facing a £28m loss due to the coronavirus pandemic.
