Yeah 5m sounds cheap, but the 50% sell-on is a real difference-maker. For all nerds on here, let`s just do some calculations
Going off BM and social media there seems to be a general consensus that he should be worth around £15m this window. Let`s assume we rather had sold him for £15m, but as a result would have to include a much lower sell-on percentage, let`s just say 20% which was the case on Lavia, and seems quite common. The 2 alternatives would equal each other if Wolves sold him on for 33m some time in the future. However, for every additional million above this, we`d get 50% rather than 20% of it.
In other words, for any future fee above 33m this lower transfer fee (but higher sell-on percentage) option is beneficial. Can easily see Doyle being sold for more than 33m at some point in the future. For example: if Wolves sell him on for 50m in the future we`d receive in total 30m rather than 25m, and that gap would get bigger the bigger the transfer fee gets. Sounds like pretty good business to me