The other one if it's accessible would be Northumberland Park as you can get to Liverpool Street or Stratford from there for the Lizzie Line connection.
As both games are cup finals there should be the opportunity to get the jump on some of the fans who stay for the presentation.
Ideal scenario would be rugby finishing at 4.30 and the football going to extra time.
Will then have the joys of post Old Firm Scottish Cup Final in Glasgow. Will probably go for an Uber over the train to Stirling for that.
Thanks all