I have an unholy set of flights booked from the US which culminates in a
transfer from Gatwick Airport to Heathrow Airport for the final leg of my
journey. I only have 3 hours between landing and take off of the next flight
(need 40 minutes check in) and I assume it will take me 40 minutes to get
out of Gatwick. This leaves me with about an hour and a half to get from LGW
to LHR.

Can anyone advise me as to the best way to do this? I'm thinking taxi, but
those Checker Cabs guys at G
Gatwick always have a laugh with prices. Last time it cost me £80 from LGW
home to Islington! Any viable public transport options?

Thanks,
David.