You can use the following text string for opening hours, it works.

Oct 1-Mar 31 09:45-16:30; Apr 1-Apr 30 08:15-18:15; May 1-Aug 31 08:15-20:15; Sep 1-Sep 30 08:15-19:15

The difficult choice is: on the park outline, on the gates or on footways? Ideally repeated but this might create inconsistency in the future if someone updates one objects and not the others.

Ping @Thierry1030: second opinion wanted.