Preheat the oven to 200°C.
Rub the lamb steaks with oil and season with salt and pepper.
Fry the lamb in a chargrill pan for 2-3 minutes per side.
Transfer the lamb to an ovenproof dish and roast for 5-7 minutes.
Let the roasted lamb rest on a warm plate for 10 minutes.
Heat the relish ingredients in a saucepan until the currants break down.
Stir the bone marrow into the bubbling relish sauce if using.
Fry the swede, potato, garlic, and herbs in oil for 8-10 minutes.
Add broccoli and seasoning, then cook for 8-10 more minutes until tender.
Slice the lamb and serve over the vegetables with redcurrant relish.