To me this looks like a hybrid Red x Black, which I personally believe fasciicauda was too. Pro Red features are among other things the reddish upper tail, the below unbarred long primaries and the darker tail corners. Pro Black includes sparsely barred upper tail, wing formula with 6 emarginated primaries (although p5 is missing you can conclude certain attributes by analyzing the shape of p6!), head of BK type, shallow tail fork, rather uniform underbody etc etc. Also status of moult fits BK better.
It appears to be a widespread phenomenon that closely related vagrant species ending up in isolated locations start to interbreed, creating hybrid populations. The “Barbary Falcons” of the Canary Islands being another great example, with huge phenotypic variation ranging from Peregrine type birds to pure-looking Barbary Falcons. Island populations can be an asset and a pitfall.