1) Preheat the oven to 190C/Gas 5.
2) In a small mixing bowl, stir together the salt, lemon pepper, dried basil and poultry seasoning. Rub the olive oil all over the hens and season each with the salt mixture.
3) Place the hens on a baking tray with plenty of space between them. You may need to use two trays. Loosely stuff the cavity of each hen with some green pepper, celery and onion. Roast the hens in the preheated oven for about 1 hour or until an instant-read thermometer inserted into the thickest part of the thigh registers 85C and the juices run clear. Remove from the oven, loosely tent with foil and let rest for 10 minutes before carving or serving.
Cook's note: Line the baking tray with foil under the wire rack for an easy clean-up. The veggies and herbs stuffed in the cavities of the hens will flavour the meat as it cooks. Be sure not to crowd the hens on the baking tray or else the skin won't crisp up properly and they will take much longer to cook.