Arm 2: CT - fluoroscopic guided transforaminal lumbar epidural normal saline (1 ml) mixed with local anaesthetic (1ml) (Active Intervention controlling for pharmacology) AND oral placebo taper (Placebo Control) Note: The Normal Saline is a Normal Saline flush 0.9% injectable solution. The local anaesthetic preparation is standardized to replicate current practice: EITHER (i) bupivacaine 0.5% (1ml) OR (ii) lignocaine 1% (1ml).