Hi Guys
Try playFullFile(playtrack.c_str()) sorted out the issue. Seems simple now but was not at 2 in the morning! So thank you arduino_new for your prompt and helpful answer.
In reply to PaulS, there are hundrends of sounds effects and it is much easier for he end user to keep track of these and what they are for used for and more importantly, when. The reason for the 8.3 filenames is that this is what the MP3 Music Maker Shield requires and will not understand any other format.
Again many thanks
Chazza