The cost is about 20 and the required forms are available from any post office. Alternatively, you must retake the full British licence test. They will supply you with a car and ensure that you have a good idea about some of the requirements of the practical test. The law is very strict in the UK regarding driving under the influence of alcohol. Not only will you be fined heavily, but you may be barred from driving for some time.
Police are constantly on the lookout for speeding and bad driving.