You can book a taxi via following methods:
Online: http://www.spotoncabs.co.uk/
Telephone: +44 172 666 6999
Email: info@spotoncabs.co.uk
Yes, it's possible to pre-book a taxi with Spot On Cabs, please contact the company.
Spot On Cabs 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.