Walk the site during rain. Mark the puddles. Note which way water runs: to the house, to a neighbour, to the road or into the garden. That sketch is worth more than a colour chart. Ask the contractor three things. 1. The fall. Which way, and how much. 2. The outfall. A soakaway, the garden, or a gully. If the road gully already backs up in October, say so. 3. The base. What depth of compacted stone, on your soil. Peat, soft ground or made-up ground near the coast needs more than a firm gravel site in town. Resin bound needs an open base so water drains through. Tarmac needs a firm base, a fall and edges that stop water getting under. A permeable surface on a sealed base doesn't work. Holiday homes at Strandhill that sit empty midweek and fill with cars at the weekend can show puddles an empty drive never shows. Photograph it with the cars on it. This is the part nobody photographs for a brochure. It's also what decides whether the drive lasts.
A drainage plan should name the fall, the outfall and the compacted depth for your soil. Without all three, it isn't a plan.
Photos of puddles during rain, the direction water runs, and whether the ground stays soft.
Atlantic rain is the design load in Sligo. A thin sealed base won't last two winters here.