I think we are due 2.5% of any Maddison transfer, as part of solidarity payments.
As he was registered for coventry between him being 12 and 18 - we accrue a certain percentage of a total of 5% for each year. Which is weighted more between the ages of 19 and 23.
So providing he is sold this year, we would be due 2.5% and Leicester/Norwich would share the other 2.5% plus whatever % of fees they have agreed.
I'm not 100% but this is what I got from a book on football finances I just finished.
The other caveat to this would be if we worked a transfer clause in, agreeing with Norwich we are due a slice of any transfer % they get from Leicester.
E.g. Leicester receive 100m, Norwich are due 20% so receive 20m. If we got 10% of the 20% then we would receive 2m.
PLUS
5% of 100m is 5m in a solidarity fund - we would then be due 2.5m in solidarity.
Bringing the total to 4.5m if he goes for 100m.
In practice, I am not sure we would have been able to negotiate that second slice of the pie from Norwich - as practically it's very hard to police and secondarily, I cant imagine Norwich giving that up.