Having owned both a 999R and a 998S this hybrid sounds the best of both worlds (at the right price!) so I reckon a 998s is £6k and a 998R is £14k, however this is neither so £7k max? Original motor no longer around.
It is in Ireland and the seller thinks it is worth 8.5k... Probably better buying a cheap 748r and doing the 1098 conversion. Engine service charges are more friendly on the newer evo motor