Heat the oil in a heavy based frying pan over a high heat. Add the steak and cook for 2 minutes on each side, then reduce the heat and continue to cook for 5-10 minutes, turning once depending on how rare you like your steak.
Transfer the steak to a plate, season to taste with salt and set aside in a warm place to rest.
Meanwhile, bring a large pan of water to the boil. Add a good pinch of salt and tip in the rigatoni, stir once and cook for 8-12 minutes, or according to packet instructions, until the pasta is al dente.
Add the shallots to the pan in which you cooked the steak, with the garlic, thyme and bay leaf. Cook for 2 minutes, stirring until the bacon strips and continue to cook until sizzling but not browned.
Add the pimentos (keep some aside and chop up to stir through your pasta) and olives then cook for a further 2 minutes.
Stir in the puttanesca sauce and then add the mushrooms and oregano. Season and continue to cook until the mushrooms are tender, stirring occasionally.
Slice the rested steak on the diagonal, cutting away and discarding any fat, drain the pasta, stir through some chopped pimento, then divide among the bowls. Put the steak on top and spoon over the sauce and serve immediately.