DW3000 Timeout Failure

I am using nRF52840 and DW3000 within the SS_TWR_RESPONDER and SS_TWR_INITIATOR examples.

Within SS_TWR_RESPONDER the function call from dwt_starttx always fails with a timeout
If I try and use it with DWT_START_TX_IMMEDIATE it succeeds, but then the initator fails with some obscure error.

It would be great to have some help, I noticed that someone else had a similar problem around 2.5 years ago with the DW1000 and never even received a response from Deca

I’m also a wee bit tired of the examples being called “simple” they most certainly are not !

                    dwt_writetxfctrl(sizeof(tx_resp_msg), 0, 1);          /* Zero offset in TX buffer, ranging. */
//                    ret = dwt_starttx(DWT_START_TX_DELAYED);
                    ret = dwt_starttx(DWT_START_TX_IMMEDIATE);

                    /* If dwt_starttx() returns an error, abandon this ranging exchange and proceed to the next one. See NOTE 10 below. */
                    if (ret == DWT_SUCCESS)
                    {
                        /* Poll DW IC until TX frame sent event set. See NOTE 6 below. */
                        waitforsysstatus(NULL, NULL, DWT_INT_TXFRS_BIT_MASK, 0);

                        /* Clear TXFRS event. */
                        dwt_writesysstatuslo(DWT_INT_TXFRS_BIT_MASK);

                        /* Increment frame sequence number after transmission of the poll message (modulo 256). */
                        frame_seq_nb++;
                    }