Britrail pass - reservations in advance?
 

I'll be spending the Christmas holidays with friends and family in Britain and will be using a First Class Britrail Pass. I know that seats are going to be tight that time so I think I should make the rail reservations in advance. I will have a First Class rail pass.

The problem is that I will only be in the UK on the 14th Dec and my trips will be on 18th, 21st and 29th Dec. Peak travel periods.

Can my friend in London make the train reservation for me? Does he need to show proof of my pass or just tell the ticket agent that I will have the Britrail pass?

Can I make the reservation outside the UK? All the train companies don't seem to accept the fact that all I need is a reservation. They want me to buy the ticket before I can make a seat reservation.

I'd just do it yourself when you get here. If you were in standard you might have more of a point but in first I'd be very surprised if you couldn't just walk onto whatever train you want and find an empty seat.