Hello, Vicky!
Welcome to planDisney, and thanks so much for sharing your good question with us!
Since you're coming in September and all the way from the United Kingdom, I think it's worth getting tickets for Oogie Boogie Bash if the party returns in 2023. The party is a remarkable experience at
Disney California Adventure, unique in its atmosphere.
And because you love Halloween, you're an adult, and you sound like a Disney person, I'd get a two-day ticket to enjoy the parks during the day
and a ticket for
Oogie Boogie Bash. It's likely a once-in-a-lifetime experience to come alone to the
Disneyland Resort in September, so I think you should make the most of it!
I hope this advice helps you plan an extraordinary trip to California, Vicky. Please let us know if you have more questions along the way. We'll be delighted to help!
May the magic be with you,
Julie