Would you recommend radical surgery for a burst disc or is there some other method of relieving pain and improving posture?

Conservative first. Conservative therapy is always best for patients rather than surgery for disk herniations as long as they do not have weakness nor any other neurologic deficit. If you do not have any of the above and your pain is manageable, try physical therapy and epidural steroid injections to see if you can avoid surgery.
Another method. A "burst disc" can be normal and asymptomatic. However, if a burst disc, ruptured disc, herniated disc, etc. Is symptomatic, radical surgery is rarely necessary. Excision of the disc often provided permanent relief of the symptoms, any postural abnormality is usually the result of spasm of back muscles that will disappear once the symptoms have been relieved.