Put the pumpkin in a colander, salt lightly, and toss. Weight the pumpkin with a plate and weights [some canned food will do], and drain for about an hour.
Trim, wash, drain, and coarsely chop the greens and herbs.
Preheat the oven to 180C.
Squeeze the pumpkin to get rid of as much liquid as possible. Heat 2 tablespoons olive oil in a large skillet [or wide pot] and cook the pumpkin until it wilts and most or all of its liquid has evaporated. Transfer to a large bowl.
Wipe the skillet clean and heat 2 tablespoons of olive oil in it; cook down the leek and onion, stirring until wilted. If using fennel bulb, cook it together with the leek and onion. Transfer to the bowl with the pumpkin.
Heat another 2 tablespoons of oil in the skillet and wilt the spinach and chard; add to the bowl. Add the remaining greens and herbs to the bowl and season to taste with a generous amount of salt and a little pepper. Reserve 8 tablespoons of olive oil; stir what remains into the greens mixture.
Divide the dough in half. Divide each of them in four equal balls. You will need 4 balls per pie.
Lightly oil to round of 20cm in diameter, 5cm deep.
Roll out the first dough ball on a lightly floured surface, using the shape of your pan as the guide. Place the dough inside, leaving about 5cm hanging over the edge. Brush with two tablespoons of olive oil. Repeat with the second piece of dough. Brush that, too, with olive oil.
Spread the filling evenly over the phyllo. Repeat the rolling process for the third sheet, placing it over the filling and pressing down gently. Brush with olive oil. Finally, roll out the last piece of dough to a slightly smaller piece and place it over the surface of the pie.
Join and fold in the bottom and top overhanging dough, rolling it around the perimeter of the pan to form a pretty rim. Brush the top of the pie generously with olive oil. Score into serving pieces. [do not cut through to the bottom]
Place in the center rack of the oven and bake for about 40 to 50 minutes, or until the pastry is golden and crisp and the pie pulls away from the perimeter of the pan. Remove, cook in the pan, and serve warm or at room temperature.