Please google :- TheLoxton Murder.
It will be found that the perpetress, Miss Noreen O'Connor, was arraigned at Somerset AssiZes. She was found 'guilty but insane', and committed to Broadmoor.
Subsequently, apparently recovered, she lived at St Andrews Hospital, Northampton, until she died in 1983.
Is it possible that she was known to June Bamber , during her treatments there? Also Sheila may have been aware of her.