If you hold a valid New Zealand driving licence or International Driving Permit you can drive in Great Britain in the vehicles covered by your licence for up to 12 months. 

New Zealand licences can be exchanged for British licences for up to 5 years from the date of entry into Great Britain. The DVLA is the government agency that handles drivers' licences. (For enquires about driving in Northern Ireland contact the Northern Ireland Licensing Authority.)

You can renew or replace a British driver's licence online.