Toss pumpkin with 2 tablespoons of the oil and thyme. Season with salt and freshly ground black pepper. Place on a baking tray and roast for 30 minutes, turning once, until cooked and lightly caramelised. Set aside to cool slightly.
Meanwhile, brush the cheese rounds with 1 tablespoon of the remaining olive oil and coat in the breadcrumbs. Place on a separate greased baking tray and chill until just before you're ready to serve the salad.
Whisk together the vinegar, mustard and remaining 2 tablespoons of oil. Season to taste with salt and pepper.
Place the goat's cheese in the oven for 5-6 minutes until crumbs are golden.
Toss the salad leaves and pumpkin in half the vinaigrette and pile onto plates. Add the warmed goat's cheese and drizzle with the remaining vinaigrette.