Personally wouldn't line the dish with pastry and leave the filling in it overnight. That's a surefire way to get soggy leaky pastry. What I would do:
1. Premake pastry and stew
2. Line pie dish with pastry, leaving enough for lid and decorations. Wrap everything and leave overnight.
3. Preheat oven, fill pie, cover with lid, crimp egg wash, bake.
Top tips for making stew:
1. If you don't like lumps of mushy, soupy, grey vegetables in your stew, put them in muslin and tie up. Then they will impart all their flavour to the stew and can be easily removed.
2. Herbs and spices are your friend. Thyme, bay, an black peppercorns should all be in a beef stew.
3. There's absolutely nothing wrong with a home cook chucking a 'Rich Beef Stock Pot' in. (Disclaimer: there are, I'm sure, other brands that will be as good if not better)
4. Probably most important: Brown off your beef thoroughly before hand. It should look like
this. Then deglaze the pan with the ale.