I haven't been to a Showmasters event in years so i've virtually a newbie again.
BUT in the past, they haven't swapped anything because it can mess up the whole system. It does clearly state when buying tix, that if you miss your photo session time slot, they cannot put you into another, so I assume that will also apply to trying to swap for an earlier session. Time slots allocated are based on X amount of people per photo batch and how many batches there are to get through. Other con companies won't usually do it either for the same reason.
Due to Jodie being so popular and only being there one day, the schedule for her stuff is already ridiculously tight without making accomodations.
As it is, the chances of non-diamond pass holders getting an autograph seems next to unlikely due to the amount of time thats had to be allocated for photo sessions.
You have a gold pass so you will go in to photoshoots next behind diamond pass holders anyway.
Tbh, I would say its going to be highly unlikely that you will be able to do anything about your situation other than try to change your flight home.
I completey appreciate that due to Covid, it affected your booking arrangements, but unfortunately, that has nothing to do with Showmasters and everything to do with how you as the attendee planned your trip.
You left yourself no wiggle room at all to allow for any delays or unforeseen events that may happen on the day that could affect the schedule and sometimes that does happen.
The fact that Jodie is pregnant too now could potentially cause delays as it could affect how she feels on the day and may need to take things slow. We just don't know .
Don't mean to sound harsh at all, and mean no disrespect, so I hope I haven't offended.
I could be wrong and someone may be able to help you better, but if I were you, I wouldn't get my hopes up and try to work on another plan. Good luck though!!!