PurplePixie As you've had the Sciatica for a long time now, and it's no better, I'd be inclined to ask your doctor about a steroid injection.
I've had a similar pain, only at the front of hip/groin, for 3 months. A Physio at the surgery insisted it's Osteoarthritis, and I was given exercises (which made it worse) and various painkillers, which had no effect. It now transpires that I've got a labral tear (of the cartilage around the hip) and am waiting to see someone at a Musculoskeletal clinic - have you been seen at one of those clinics?