Pre heat the oven to 200°C.
Bring a pan of salted water to the boil, then cook the potato for a few minutes (until they have started to soften slightly) Drain them and do the same with the carrots.
Cut 4 slices of lemon (about the thickness of a pound coin) and set the remaining lemon aside.
Spray a large baking tray or roasting tin with some low calorie cooking spray, then place the chicken on the tray and season.
Put the part cooked potato wedges and carrots into a large bowl and add the slices of garlic. Spray with some low calorie cooking spray and season with some salt and pepper. Add the thyme and then squeeze some of the juice of the remaining lemon into the bowl. Toss to mix well.
Add this to the tray with the chicken on, arranging the veg around the chicken
Cook for about 30 minutes.
While the chicken is in the oven, cook the green beans in a pan of boiling salted water for 2 or 3 minutes. You want them to retain their colour so don't cook then for any longer. Drain, then season and add the lemon slices and a little more of the juice from the lemon
After 30 minutes add the green beans to the tray and return to the oven for 10 - 15 minutes.
Make sure the chicken thighs are cooked and the carrots and potato are soft. Serve immediately.