i don't really know how to help you or what you can say to your dentist but i do know that when you have an issue with your bite (as i've definitely had) it is terrible and you feel like it will never be normal again. i was constanly focusing on how my teeth came together (or didn't!!) and got really depressed about it. my issues were also caused by bad dental treatment so i understand that too.
i think, unfortunately, that it will be quite difficult for you to truly get this problem sorted out on the nhs. my experience has been that correcting a bite problem takes lots of time, study models of your teeth must be taken, and small adjustments made until it gets 'just right'. any dentist who doesn't take the time to do this might make your bite even worse and have to go shaving bits of teeth and crowns all over the place!!
the treatment i had consisted in (something like this anyway, i can't completely remember all the details):
step 1: full night guard to relax the jaw and so dentist could see where i was biting/grinding etc
step 2: study models made of my teeth
step 3: adjustments made on study models to check accuracy
step 4: adjustments made on my teeth (although i didn't get to this stage becasue i decided to have braces instead!!)
braces are another option, although they might not be suitable in your case, i don't know.
anyway, all of this treatment is expensive, and that's what happens too much for my liking: NHS dentists mess our teeth up and then we have to pay £££ to correct their mistakes...
sorry i can't be of more help but, if you find the right dentist, i'm pretty sure you'll get there in the end!