ok I've looked at it a little more closely and I think I can just do this
for (int i=0;i<12;i++){
switch(i){
case 0 :Serial.print("Time in UTC (HhMmSs): ");break;
case 1 :Serial.print("Status (A=OK,V=KO): ");break;
case 2 :Serial.print("Latitude: ");break;
case 3 :Serial.print("Direction (N/S): ");break;
case 4 :Serial.print("Longitude: ");break;
case 5 :Serial.print("Direction (E/W): ");break;
case 6 :Serial.print("Velocity in knots: ");break;
case 7 :Serial.print("Heading in degrees: ");break;
case 8 :Serial.print("Date UTC (DdMmAa): ");break;
case 9 :Serial.print("Magnetic degrees: ");break;
case 10 :Serial.print("(E/W): ");break;
case 11 :Serial.print("Mode: ");break;
case 12 :Serial.print("Checksum: ");break;
}
for (int j=indices[i];j<(indices[i+1]-1);j++){
if (j == 2) lat = linea[j+1];
if (j == 4) long = linea[j+1];
Serial.print(linea[j+1]);
though now I'm not sure what the purpose of (indices[i+1]-1) is.