Apostles Back House is in Catacol, on the west coast of Arran. It's behind the row of cottages called the Twelve Apostles, so you're just set back from the front. It's a one bedroom place for two people. You get a little patio garden out the back.
The rating is 4 Star. It's been renovated, it's clean and comfortable. The shower is good. It's all on one level inside, which is handy. The kitchen is part of the living room.
You're right by the shore. It's a pebble beach, not sand. You can see seals sometimes. There are red squirrels about. The village is tiny, just a few houses. It's very quiet.
You can walk straight from the door. Up the glen, or along the coast road to Lochranza. The bus stops in the village if you don't want to drive. Lochranza has the whisky distillery and a castle ruin. The distillery does tours.
For a bigger shop or a restaurant, you'd drive to Lochranza or round to Pirnmill. Brodick is about a 40 minute drive. It has the ferry, the main shops, and Brodick Castle. The island golf courses are good if that's your thing.
It says pets are allowed, up to two. The bedding and towels are included. There's a washing machine, WiFi, and a TV. Parking is on the road outside the cottage.
Useful links: Arran National Nature Reserve for the whitebeam trees and walking, and VisitScotland Arran for general trip planning.