You can book a taxi via following methods:
Online: http://www.matrixcarhire.co.uk/
Telephone: +44 208 212 7285
Email: info@matrixcarhire.co.uk
Yes, it's possible to pre-book a taxi with Matrix Hire, please contact the company.
Matrix Hire 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.