Concurrent Scan and Advertise NRF_ERROR_NOT_FOUND on ble_advertise_start

Question

I am trying to build an application where the device scans and on receipt of a packet with certain data in it, advertises for a short while, using both advertising and scan response data in both the scan and advertisement. 
 I have been stuck for a few days now with the error ERROR 5 [NRF_ERROR_NOT_FOUND] 
 This is returned by sd_ble_gap_adv_start, which seems to indicate that either the adv_handle or conn_cfg_tag is not found. 
 I have tried any number of things, including stopping scanning before starting advertising, adjusting scan window, interval, advertising interval, using the default conn_cfg_tag, using the app conn_cfg_tag, using the NONCONNECTABLE advertising mode etc. 
 Initialization: void bleStack_init(void)
{
 ret_code_t errCode = nrf_sdh_enable_request();
 APP_ERROR_CHECK(errCode);
 
 // Configure the BLE stack using the default settings. Fetch the start address of the application RAM.
 u32 ramStart = 0U;
 errCode = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ramStart);
 APP_ERROR_CHECK(errCode);

 // Enable BLE stack.
 errCode = nrf_sdh_ble_enable(&ramStart);
 APP_ERROR_CHECK(errCode);
 
 NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, &eventhandler, NULL);
 
 NRF_LOG_INFO("Stack Initialised!");
}

void bleScanDrv_init(void)
{
 ret_code_t result;
 nrf_ble_scan_init_t bleScanInitStruct;
 memset(&bleScanInitStruct, 0, sizeof(bleScanInitStruct));

 bleScanInitStruct.p_scan_param = &bleScanParamStruct;
 bleScanInitStruct.connect_if_match = false;
 bleScanInitStruct.conn_cfg_tag = APP_BLE_CONN_CFG_TAG;

 result = nrf_ble_scan_init(&bleScanInstance, &bleScanInitStruct, bleScanEventHandler);
 APP_ERROR_CHECK(result);

 #define ENTITY_DEVICE_UUID {0x42,0x00,0x74,0xA9,0xFF,0x52,0x10,0x9B,0x33,0x49,0x35,0x9B,0x8A,0xCA,0x68,0xEF}
 #define ENTITY_DEVICE_UUID_SHORT ((u16)0xCA8A)

 BleUuidShort entityDeviceUuid = 
 {
 .uuid = ENTITY_DEVICE_UUID_SHORT,
 .type = BLE_UUID_TYPE_VENDOR_BEGIN,
 };

 BleUuid entityDeviceUuidBase = ENTITY_DEVICE_UUID;

 result = sd_ble_uuid_vs_add(&entityDeviceUuidBase, &entityDeviceUuid.type);
 APP_ERROR_CHECK(result);

 result = nrf_ble_scan_filter_set(&bleScanInstance, SCAN_UUID_FILTER, &entityDeviceUuid);
 APP_ERROR_CHECK(result);

 result = nrf_ble_scan_filters_enable(&bleScanInstance, NRF_BLE_SCAN_UUID_FILTER, false);
 APP_ERROR_CHECK(result);
}

void bleAdvertiseDrv_init(void)
{
 // Register gateway advDataHandler
 bleGatewaySvc_registerAdvDataHandler(gatewayAdvDataHandler);

 //DECL_INIT_VAR(ble_advertising_init_t, advInitStruct);
 memset(&advInitStruct, 0u, sizeof(advInitStruct));

 // Set advertising speeds and timeouts
 advInitStruct.config.ble_adv_on_disconnect_disabled = false, /**< Enable or disable automatic return to advertising upon disconnecting.*/
 advInitStruct.config.ble_adv_directed_enabled = false, /**< Enable or disable direct advertising mode. */
 advInitStruct.config.ble_adv_fast_enabled = true, /**< Enable or disable fast advertising mode. */
 advInitStruct.config.ble_adv_slow_enabled = false, /**< Enable or disable slow advertising mode. */
 advInitStruct.config.ble_adv_fast_interval = ADV_INTERVAL_MS_TO_VALUE(APP_ADV_INTERVAL_FAST_MS), /**< Advertising interval for fast advertising. */
 advInitStruct.config.ble_adv_fast_timeout = ADV_DURATION_MS_TO_VALUE(APP_ADV_DURATION_FAST_MS), /**< Time-out (in units of 10ms) for fast advertising. */

 advInitStruct.evt_handler = &advertiseEventHandler;
 advInitStruct.error_handler = &advertiseErrorHandler;

 const u8 deviceNameDefault[] = "Device";
 
 ble_gap_conn_sec_mode_t sec_mode;
 BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);
 u32 result = sd_ble_gap_device_name_set(&sec_mode, (const u8 *)&(deviceNameDefault[0]), 6u);
 APP_ERROR_CHECK(result);

 // Update advertisement data
 s8 txPowerDefault = 0u;
 
 //memset(&advData, 0, sizeof(advData));
 advInitStruct.advdata.name_type = BLE_ADVDATA_FULL_NAME;
 advInitStruct.advdata.include_appearance = false;
 advInitStruct.advdata.flags = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
 advInitStruct.advdata.p_tx_power_level = &txPowerDefault;

 // Update scan response data
 advInitStruct.srdata.name_type = BLE_ADVDATA_NO_NAME;
 
 ret_code_t errCode = ble_advertising_init(&advInstance, &advInitStruct);
 APP_ERROR_CHECK(errCode);

 ble_advertising_conn_cfg_tag_set(&advInstance, APP_BLE_CONN_CFG_TAG);
 didTxPowerDrv_setAdvertisePower(advInstance.adv_handle, didTxPowerDrv_Level_4dBm);
} 
 Advertising start: 
 // Message from scanResponse event handler to start advertising
static void scanResponseHandler(void *data, u16 size)
{
 if(!advStarted)
 {
 // Using this in order to update advertising data
 u32 result = ble_advertising_init(&advInstance, &advInitStruct);
 APP_ERROR_CHECK(result);
 
 // Start advertising
 result = ble_advertising_start(&advInstance, BLE_ADV_MODE_FAST); // NRF_ERROR_NOT_FOUND occurs here
 APP_ERROR_CHECK(result);

 advStarted = true;
 }
}