Audio Fixing - Denoiser, Deesser type job

I'm working with a short piece of audio (2min30sec) for community river education piece about our local river history and something funny is happening with the audio on these narration snippets I've been given - just noisy and too much sibilance.

I've tried the standard Denoiser & Deesser that comes with FCPx but I feel like these tools distort the audio too much... I just want it cleaned up. I'm more of a visual artist than an audio expert and I just have not been able to get it clean without distortion.

I have a feeling this is the kind of thing that someone with an ear & experience repairing audio will be able to fix quite easily.

Please have a listen to the audio in question before bidding on the project. PPH has a file size limit, so just uploading MP3 for sample but will send you .WAV once offer is accepted.

Thanks so much!