Season flour with good pinch of salt and plenty of pepper dust the lamb shanks in seasoned flour.
Heat oil in a large heavy based casserole dish and brown shanks all over getting good coloring on all sides, add remaining flour, onions and garlic and stir well. pour in wine to deglaze followed by stock, rosemary, redcurrant jelly and a healthy grind of pepper.
Bring to the boil, cover and turn down heat to cook at a very gentle simmer for around 2 hours untill meat falls off the bone and the sauce is rich and thickened. Remove bones reserving 3 of them and flake meat into small pieces.
Preheat oven to 200 degrees
Fill a two litre pie dish with the lamb filling. Roll pastry to about 3mm think and around 2.5cm larger than the dish. Cut a 2cm stripe from the pastry. Brush the rim of the dish with a little water and place stripe around the rim, pressing it down.
Sit the 3 remaining shank bones at intervals along the length of the filling these will act as pie funnels releasing steam when baking and also stop pastry from sinking into the pie filling and becoming soggy.
Cut 3 slits in pastry lid at same intervals as the lamb bones, place on top and slide over bones. Press down edges of the pastry to seal. Trim off any excess and crimp the edges with a fork. Brush with beaten egg and bake for 30-35mins untill pastry is crisp and golden.