As a UK citizen, with an easy to understand accent, I believe I am best placed to deliver this training for you. As I understand, you would like recordings of the email being corrected, as if in a classroom situation ?
To give you an indication of the quality of english that I can provide, I have corrected the email that you supplied - I hope that this meets with your requirements.
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Dear Sir, (although I would make a comment on the video that addressing to the specific person would perhaps be better)
We are specialists in fibreglass manufacturing - our main products are chopped strand mat (CSM) and stitched chopped strand mat. We are able to supply this from our factory in China at high quality and very competitive prices. Please see our website for more information : www.fiberglassproducer.com.
If you are interested in our products and would like further information, or would like a no-obligation quote for comparison purposes, please reply to this email.
We look forward to working with you in the near future.
Kind Regards
Jack