Problem for me is that Branthwaite still looks a bit shaky at times - unsurprisingly for his age - so a club is still buying potential rather than the finished article, and I'm not sure Amorim will get the chance to see Branthwaite become the player that Utd want to buy. Also, not being named by Tuchel in the England squad is a massive kick up the arse for the lad to move to a "higher profile" club, which seems to be how you get in the national squad.
Having said that, Rashford actually had to move away from Man U to get in the England squad, so Branthwaite should probably be looking elsewhere if that's his aim. Anyway, I'd be surprised if we got more than £55m plus a few add-ons for him this summer, unless the RS come calling, which would be a whole other thing.