Having recently discovered that you can buy through tickets from tube
stations online[1], I have a U123 Londn to Evesham off-peak return
(with Railcard discount) for today[2].
I know that the off-peak restriction applies to the FGW service from
Paddington, but will the ticket be valid for tube connections in the
afternoon peak, ie if I leave home before 1900?

[1] At least, from WebTIS retailers, like East Coast
[2] As an aside, I've also booked a U123 to Pollokshields West Advance
First Class ticket for later in the month. Where do I present my
ticket on the tube for my free tea?