Hi Maria
This is a difficult one - and I think you have to go with your gut instinct. The fact that they asked you if it was okay for the accessor to access his previous medical records sounds positive, but as you pointed out in your post, you're not sure you trust the DWP. Whether you send it again, there is no guarantee that an assessor will read it before they speak to you - I hope they will - but they don't always. Some members will say - send again - and some will tell you not to - so that's why you have to go with your gut instinct and do what feels right for you.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems