Preheat the oven to 180C degrees.
Place the chicken in a large roasting tin.
Cut the onion in 4 wedges. Smash the garlic cloves lightly. Cut the pepper into 8 large chunks. Put these around the chicken.
Scatter the oregano all over then season with salt and pepper. Squeeze the lemon juice all over, then cut the lemon into 4 wedges and tuck them between the chicken legs.
Drizzle everything with olive oil, then put the tin in the oven.
After 15 minutes turn over the chicken legs and add the tomatoes.
Bake for 20 minutes, turn the chicken back and scatter the olives around. Cut the cucumber into 2cm chunks, and tuck these between the chicken and the vegetables.
Bake for another 10 minutes or, until the chicken is golden.
Serve the chicken with the baked vegetables and the pan juices. You can scatter some feta on the top if you like.