G-CPTN :
Wouldn't a go-around have put the arriving aircraft into the same airspace as the departing aircraft?
Definitively, with that your chances of getting them together and not seing each other is very high.
From the full report :
Data provided {...} shows that the departing aircraft became airborne prior to the landing aircraft touching down.
In my years this would have never made an incident entry.
A storm in a glass of Guinness..