City Cabs website suggests a 30 mile journey would cost £1.90 a mile.
So ... £57 divided by four = £14.25 a head.
It may be more, of course, because it's late at night.
But check first and book via 01273 205205.
Travel by train!
Falmer to Brighton (dep Falmer at 2157)
Brighton to East Croydon (dep Brighton at 2219)
East Croydon to London Bridge (dep East Croydon at 2302)
London Bridge to Tunbridge Wells (dep London Bridge at 2339)
Arrive Tunbridge Wells at 0027
Three different train operators, so no...