QUOTE(petrat @ Apr 3 2008, 10:43 PM)

The first three notes could be the start of dozens of pieces, but it is not Suo Gan that I am hearing. It is a big cello theme with an orchestral accomp. I have included this theme in one of a set of sketch book pieces for Idris, (grandson) who is now one year old. I have used flute, oboe, bassoon, violin, cello and harp but I still have this feeling that I have heard it before and played it too. I hope that it is an original theme of my own but...............

I've just tried the rest out and it doesn't seem at all familiar.
Your story reminds me of Paul McCartney's report of writing "Yesterday" (I think) which - if I remember rightly - is that he woke up with the tune is his head and it seemed so familiar he kept singing it to people, asking who had written it - and couldn't believe that no-one already had.
It also reminds me of the time my sister and I were practising for our grade 5 theory exam. My father was checking what we'd done and my sister got very upset when he told her that the melody to which she had set the given words was all very well but unfortunately Mendelssohn had written it first. I, on the other hand, was upset that I hadn't composed anything that sounded if it had been written by someone else first.
Reminiscing back to the 1960s... oh dear showing my age!