Fair enough. They know it's more than £70m.Yes it is, but Arsenal don't know what that figure is. So when you said 'Arsenal know what they need to offer to sign him' - no, they don't
Albion don't want to sell. They want to buy. So, if they want him, keep putting in offers. TB and co will tell them when they've hit the right number. But right now, the message being communicated is that as far as the Albion are concerned, he's not for sale. So, Arsenal know they just need to keep upping the offer, or go away.