I have got it to work ok.   In my first trials I tried using the RTC to ASCII conversion.  However, there was an unsuccessful write with the transfer status keeping on throwing up a no. 8 error (correct...no. 8!) for some reason, so I eventually gave up and tried another path.  After Joe's suggestion, I went back to the original idea using the parameters shown in the attached jpg...it is very wide to show the ladder, Sd write settings and also the results of 3 successful runs viewed via SD Car