Arm 1: CT - fluoroscopic guided transforaminal lumbar epidural steroid (1 ml) mixed with local anaesthetic (1 ml) (Active Intervention) AND oral placebo taper (Placebo Control) Note: The injectable steroid and local anaesthetic preparation is standardized to replicate current practice: EITHER (i) betamethasone injectable 5.7 (1ml), a particulate corticosteroid with the local anaesthetic bupivacaine 0.5% (1ml) OR (ii) dexamethasone injectable 4mg (1ml) a non-particulate corticosteroid with local anaesthetic lignocaine 1% (1ml).