Does anyone know when you should arrive for this and what time it’s finished.

For a 3pm kickoff on a Saturday

Jimmy Mac Hospitality opens 2 hours before kick off with food served 90 minutes prior to the game starting so I'd imagine it's the same. The bar stays open for an hour after the final whistle.

12 noon onwards
I get there for around 12.30 on saturday games

Officially opens 2.5 hours before kickoff, bar closes an hour after full time. You should get an email before the game with all the details.