You can book a taxi via following methods:
Online: http://www.gatwickexecutivecars.co.uk/
Telephone: +44 129 322 0707
Yes, it's possible to pre-book a taxi with Gatwick Executive Cars, please contact the company.
Gatwick Executive 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.