Where two people register in Scotland as civil partners of each other, the civil partnership is void if, and only if—
they were not eligible to do so, . . .
though they were so eligible, either of them did not . . . consent to its formation , or.
at the time of registration one of them who was capable of consenting to the formation of the civil partnership purported to give consent but did so by reason only of duress or error.
In this section “error” means—
error as to the nature of civil partnership, or
a mistaken belief held by a person (“A”) that the other person with whom A purported to register a civil partnership was the person with whom A had agreed to register a civil partnership.