We are doing the same train journey but on the same day sunday, we decided to go for open tickets due to not knowing how long we could get delayed getting from the ground back to Euston, plus if it goes to extra time we could of been pushing it.
3pm till 5pm normal time, extra time half hour plus the time between, then you could have penalties, watching the team parade the cupp (if we win) getting out the ground and then the delays getting to the station for a half hour trip to euston.
Our return tickets are open, as with all off-peak returns! Checked before booking just in case that happened 8)