You can book a taxi via following methods:
Online: http://www.bizzybeescars.com/
Telephone: +44 121 667 8888
Yes, it's possible to pre-book a taxi with Four Cars, please contact the company.
Four Cars has both regular and air-conditioned taxis, please mention your preference at the time of booking.
Please contact the company on their helpline number to make any changes.
Generally drivers will meet the passengers at the arrivals on airport pick ups but do check with the company.