The Olive Tree is one of those restaurants where the basement setting, low-lit, stone-walled, unhurried, does as much work as the kitchen. The cooking is modern British with a close interest in local and seasonal sourcing; the tasting menu is the natural order but the à la carte is equally considered. The wine list is serious.
The Queensberry Hotel above it is well-run if you're looking to stay. Lunch is better value than dinner and the same quality. Book well ahead for weekends.