Thanks for the reply.
I am using the default SPI that the ESP32 Core uses when 'ESP32S3 Dev Module' is selected.
I said above I was using SPI.begin() etc and I am not doing an assignment such as;
SPIClass sdSPI(FSPI);
Just the SPI.Begin();
The pinouts you quote dont seem to match those on the Espressif pin map, but work for me with for instance SCK on 12;
Maybe the pinouts you posted are for a plain old ESP32, and not the S3 varient ?