Thanks all! We ended up having a nice big breakfast and leisurely morning then went to platform 9 3/4 which worked well to take the picadilly line to heathrow from there!

Glad it worked out for you!

Best choice.

I didn't think a stadium tour would actually have worked but I gave you the info if you were brave enough to try it. You would have been stuck waiting for them 2.5 to 3 hours at very minimum.