Hi
I had a listen and a play with noise reduction software, but with the time available I didnt manage to get rid of your distortion im afraid. Its pretty harsh in places.
To improve it a little with eq only try rolling off a little of the LF around @100hz and a little MID freq notch at about 1k with a Q of 1.0. And last drop off a little HF at 6k ish as the LF drop makes it sound a little bright in the balance. This reduces the noticability of the distortion, but doesnt remove it leaving everything else in tack, which is what i was hoping for.
There is a software called spectral Layers from Divide frame (now being distributed by Sony which might be worth a look. I dont have it (yet) but Im told its very good too. These restoration softwares are a steep learning curve. Im sure there will be a demo you can try it out on free?!
I think a specialist restoration engineer with tools like cedar might be able to do more for it. Depends on budget if youve got money to spend on the full fix. A specialist who spends their days doing this sort of thing will be able to get much better results than me because of practice, experience, tools and training.
Of course nothing is as good as getting the recording right in the 1st place!
Cheers
Peter
Post Production Dubbing Mixer