There is no truth in the '6 months' report but I would advise a thorough examination before buying, as much seems to depend on the type of deafness. I have suffered 'gunfire' deafness since WWII and, in spite of first class treatment over many years, including much trialling with analogue and digital aids, nothing has helped me. Don't be persuaded by advertising into spending a small fortune. Stay, if you can, with the NHS although I'm surprised by the audiologist's statement. Was he a doctor?
I have worn 'in the ear' aids in trials for years. In the end there was obviously nothing wrong with the aids - just me.
Good luck.