Thanks for all the replies. I guess I've just been a bit impatient!

Ray,

I used pectic enzyme both before fermentation started and again after
it had finished. I don't know if pectin was present after fermentation
but have since read that I can test for it with methylated spirits.
Fortunately, I didn't lose very much wine with the racking I've done so
far presumably because I hadn't left it long enough for much sediment
to fall!

Dar V,

I'm going to transfer the wine into four or five demijohns so that I
can drastically reduce the amount of air sitting on top of the wine and
then I'll leave it in the dark for a few months before checking it
again. Would leaving maybe an inch between the top of the demijohn and
the bung be a suitable buffer?

Thanks very much for your help.