It's a weird one. I managed once to use it on the 1A at about 8:15am before heading for a full day at the office then onto an evening kick off. I had to blag it though; when the driver said "You can only use it to go to the football" I replied "I am - I'm just going to the office on the way"...
The bus driver this morning told me this morning that it was a maximum of 90 minutes before kick off which is obviously a load of bullshit.
I've looked at the official travel guide and there's no indication. Any ideas, fellow tightwads?