Universal covers of dimensional dual hyperovals

In Section 2 of [1] C. Huybrechts (2002) introduces the notion of covers and quotients of dimensional dual hyperovals and calls maximal covers universal. S. Yoshiara (2004,2006) [2] and [3] calls such maximal covers simply connected. Given a dimensional dual hyperoval, one may ask, if there exists a unique (simply connected) maximal cover of the given dual hyperoval. We shall show, that this is true. We also show, that the automorphism group of a quotient of a simply connected dimensional dual hyperovals is isomorphic to a subgroup of the automorphism group of its cover.