Peregrine peach in greenhouse
 

I have a Peregrine peach tree in my greenhouse. I followed the kind advice
of posters on this group earlier in the year and carefully assisted the self
pollination process with a soft brush. As in previous years, the
developing fruits are failing to thrive and eventually fall away. I have
just one left this year! The plant itself is lush, rampant and pest and
disease free. I perhaps fed it too well when I planted it and it 'feels' no
need to propagate itself. Is it worth persisting or should I try to move it
next back end to a rather less fertile and protected position. Any special
tips on summer pruning under the circumstances?

Many thanks.