FENZ has an easy to use tool on its check it's alright website where you can check if and when you can light a fire. Fill out your details in the 'can I light a fire?' tool and it will tell you what season it is, the fire risk, whether or not you can light a fire and any permits you need.
What 'restricted' and 'prohibited' fire season mean:
Open - No fire permit is needed to light a fire in open air.
Restricted - A permit is needed to light a fire in open air.
Prohibited - There is a total ban on the lighting of any fires in open air.