Ok, here's the fuller story and the situation I'm in.

I found a CW fare in the ex-US sale last week. It's for TPA-CLT-IAH-LHR-IAD-MIA-TPA.

It's really handy for me as I can meet people in IAH before heading to London for work. I also chose it because there's F redemption availability on both transatlantic legs. I found the fare on Matrix but when I called BA to book it there price was significantly higher. So I called a travel agent who was able to book at the Matrix fare price on a 125 ticket.

When the travel agent contacted BA to apply the Avios upgrades they were told it wasn't possible. It's not because of the rule regarding non BA sectors on the booking but was apparently because BA say "they won't issue an upgrade on a ticket they would not have naturally booked on their ticket stock".

I've never come across this before which isn't surprising as I normally book with airlines on their web sites.

The F availability is still there and I'm trying to get some clarity on the situation and determine whether there's any way around this mess.