Playing audio files from SD on ESP32

I want to play two audio files one after another on an SD card with an ESP32.

My code is below but does not work, I am pulling my hair out to work out why....

I know wiring is correct as single audio files can be played when audio.connecttoFS(SD, "charging.mp3"); is placed in setup as per demo code I based script on but won't work when called from main loop.

/*
  ESP32 SD I2S 
  Plays MP3 file from microSD card
  Uses MAX98357 I2S Amplifier Module
  Uses ESP32-audioI2S Library -  https://github.com/schreibfaul1/ESP32-audioI2S 
*/

// Include required libraries
#include "Arduino.h"
#include "Audio.h"
#include "SD.h"
#include "FS.h"
 
// microSD Card Reader connections
#define SD_CS          5
#define SPI_MOSI      23 
#define SPI_MISO      19
#define SPI_SCK       18
 
// I2S Connections
#define I2S_DOUT      26
#define I2S_BCLK      27 
#define I2S_LRC       25
 



 // Create Audio object
Audio audio;
 
void setup() {
    
    // Set microSD Card CS as OUTPUT and set HIGH
    pinMode(SD_CS, OUTPUT);      
    digitalWrite(SD_CS, HIGH); 
    
    // Initialize SPI bus for microSD Card
    SPI.begin(SPI_SCK, SPI_MISO, SPI_MOSI);
    
    // Start Serial Port
    Serial.begin(115200);
    
    // Start microSD Card
    if(!SD.begin(SD_CS))
    {
      Serial.println("Error accessing microSD card!");
      while(true); 
    }
    
    // Setup I2S 
    audio.setPinout(I2S_BCLK, I2S_LRC, I2S_DOUT);
    
    
}
 
void loop()
{
 
    audio.setVolume(15);
    audio.connecttoFS(SD, "charging.mp3");
    delay (10000);
    audio.connecttoFS(SD, "fire-full_power.mp3");
}