Preheat oven to 200°C with rack on lower middle shelf
Put chicken on oven tray with rack
Soften ½ butter, mix with garlic, dill, 1tbsp of herb rub
Cut remaining butter into 1cm strips for inserting under skin
Gently loosen and separate the skin, starting at the breasts, as far down as possible
Push butter sticks down between skin & meat, stuff some of the herbed butter in, rubbing it all over
Cut lemon in half. Push ½ lemon up cavity of bird, then the bunch of mixed herbs, then other half, some of butter mix
Rub remainder of butter all over, including underside
Drizzle with oil (lemon infused is best). Close cavity and season with salt & pepper
Cook at 200°C for 15 mins, baste, then 170°C for 1 ¼ hours(ish), basting every 15 mins, temping every 15 mins in last ½ hour
Once cooked, flip chicken upside down on rack, cover with foil and rest for 15 mins
Keep carcass for stock