Stutter age 3, problems for over 12 months

[Jo5476]

My DS started stuttering out of the blue when he was just over 2. He was showing signs of tension and so we saw a therapist who have us advice. The stutter went away for 6 weeks then returned, but differently. He was repeating words not starter of words, but he did this a lot. We continued with special time, talking slow etc. When he was three and a half it went away for almost 4 months and during this time just appeared when he was excited which is normal for his age. Then in June it returned and we can find no reason. It has gradually been getting worse but whole phrase repetitions this time, and for the last few days he has been showing tension and had about 6 blocks today where he is just breathing fast to get the word out. We have booked into a private therapist and are so awaiting an NHS appointment. It is now 19 months since it first started, although in this time it has been coming and going. Could it still go away with some therapy? He doesn't start school for another year and is nearly 4. Should I expect him to have a long term problem?