You can book a taxi via following methods:
Online: http://www.driveuhome.co.uk/
Telephone: +44 333 577 6007
Telephone: +44 785 241 0530
Yes, it's possible to pre-book a taxi with Let Me Drive Ltd, please contact the company.
Let Me Drive Ltd 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.