Ramsdale also didn't have a good season under his belt but couple of mediocre ones for example taking over from Deano where he looked rubbish. Ramsdale has around 150 games and Deano around 120 games.Ramsdale is younger, better and alot more games under his belt at top level. 20m sounds fair on a GK like Henderson
So I don't see how 20m is a fair price.
That said not many teams are looking for a keeper and Deano probably isn't that much better than many there so what the feck do I know. Plus Nick Pope is probably available.