Bluno iOS write 'buffer'

I want to update some variables on the Bluno from iOS but writes seem to build up in a buffer and drain slowly.
Here I'm sending the value from a UISlider, as a 4 byte packet, but only after checking bReadyToWrite.
If I change the UISlider, TX/RX will flash for a few seconds after as the 'buffer' empties making update very unresponsive.

[code]- (IBAction)speedChanged:(UISlider *)sender {
    if (self.blunoDevice.bReadyToWrite)
    {
        short int value = (sender.value - 0.5f) * 65535;
        NSData *dataPacket = [self dataPacketWithTag:TAG_SPEED value:value];
        [self.blunoManager writeDataToDevice:dataPacket Device:self.blunoDevice];
    }
}[/code]

[code]void loop()
{
if (Serial.available() >= PACKET_SIZE) {
    if (Serial.read() == HEADER) {          // 1st byte
      char tag = Serial.read();                //  2nd byte
      if(tag == TAG_SPEED)
      {
        val = Serial.read() << 8 ;      //  3rd Byte - data MSB
        val += Serial.read();            //  4th Byte - data LSB
        Serial.print("Speed:");      // Hundreds of these coming through very slowly.
        Serial.print(val);
        Serial.print("\n");
      }
    }
  }
}[/code]

Can I speed this up somehow? Or at least find out when Bluno is REALLY ready for another write?