If its England caps, champions league appearances, % sell on above £10m - then its worth very little.
If he turns out to be as sucessful as that ie an England player playing in the champions league, then we have sold him cheap if all we get is £7m. Without knowing the full detail on this its hard to judge this deal but IMO the key factor is the cash up front, all the other add-ons have too many variables in them, so difficult to value. What's worth more
£2m cash plus £1m when he makes his full England debut or £2.5m cash now, I'd take the £2.5m cash. Talk of £7m is over optimistic IMO.