Clue: Solver's Scottish isle (5)
Answer: LEWIS
Explanation: Definition: Solver
Double definition – the "isle" is actually just a part of the largest island of the Outer Hebrides. The "solver", I presume, is Inspector Morse's sidekick and successor, so a "solver" of cases, and/or "Mrs B Lewis", aka Dorothy Taylor, a Ximenes and Azed solver, after whom Colin Dexter named the character.