Heat the oil in a frying pan and brown the bacon and sausages all over. Put them into a broad shallow casserole or ovenproof dish. Add everything else, except the breadcrumbs, and season well.
Sprinkle a third of the breadcrumbs on top and cook in an oven preheated to 180 c, 160 Fan Gas 4 for 2 hours. Sprinkle on the rest of the breadcrumbs in two separate goes during the cooking time. Stir in the previous sprinkling of crumbs before adding the next lot.
Taste and adjust seasoning towards the end of the cooking time, then serve.