All flowers and no fruit

[shirlton]

My Pattypan plants are really healthy. Loads of flowers but no fruit. Any reason for this. All the other squashes are ok.

[shirlton]

[dtw]

Mine are the same, just male flowers.
Must be something to do with the lack of sunshine.

My pumpkins are doing really well.
I just caught a slug creeping across one of them, he (or she) has been
chucked over the fence (onto the communal grass, not a neighbour's garden).