Kokeshi - read this entire thread and each time I read a new post by I was ready to post a bit of support about my DH and his family, some of whom suffer from hearing difficulties - but each time I would read another post from you updating on the situation until there was not really a lot of supoprt I could offer as my experience does not go that far.
My DH is completely deaf in his left ear. And his DM has a perferated ear drum and has just regained some degree of her hearing after 2 years of tests and finally a gromit, following - like you a head cold - but she is still with hearing aids. Having hearing aids (the large behind the ear type) means people can tell she has a condition which affects her communication.
DH however refuses to wehre one and like yourself has no outward sign of a problem. We have developed habits for coping, and although the situation is not as severe as yours perhaps they can help your DP to help you.
In restsuarants or other out and about places face the main room and allow DP to order for you - or at least be prepared in case the waiter asks questions of your choices.
Allow DP to answer the phone and where ever possible do all the talking.
Ask DP to walk on your best side so you can still communicate while out.
Make sure you and DP have told as many of your friends and family as possible about your condition so there are no misunderstandings.
(When DH and I first started dating our first big row was because he had'nt told me of his condition - because he felt ashamed or vain I guess - and we had ordered a takeaway but I had been stood the wrong side of him so he had not properly heard me ask him something and was not expecting what we ended up with)
Finally with regards to work - are you freelance?? I work in an Occupational Health Dept, and a lot of my focus is on helping people in the work place who have conditions which may otherwise render them unable to work. There is loads of technology, as well as organisations out there who can provide you with support and advice on working with your condition rather than just feeling like you are coping.
All the best, I hope I have been of the tiniest bit of help or support if nothing else.
Also did'nt see anything else about your dad on the thread - hope things are okay, my thoughts are with you! (())