Heat the oils in a large nonstick wok or frying pan over a high heat. Add the leeks, celery, carrot and red pepper and stir-fry for about 3–4 minutes until softened.
Add the pak choi, squid and five-spice powder to the pan and stir-fry for about 2–3 minutes until the squid is just cooked through, being careful not to overcook otherwise it will turn rubbery.
Stir in the soy sauce, rice wine and sweet chilli sauce, season with salt and pepper and heat through, stirring. Serve with cooked rice or noodles.