I have noticed over the last week or so that my westie has been not hearing things. I put it down to selective hearing at first. However on Friday morning he started whining at 5am but was ok once I got up. He is eating, playing, lively etc however I noticed that his left ear is very droopy almost like it has moved down his head a little! and he seems to be rubbing it on furniture and it appears quite hot to the touch.
When I first had him he had ear mites and I got rid of these using otodex. Last night I put some otodex in and he appeared to really enjoy when I rubbed it into his ear, however a load of thick dark gunk came out, he appeared to be a little better and settled last night without whining etc.
Has anyone any ideas? Is it just mites would this cause his apparant loss of hearing and a hot drroppy ear, I suspect it is hot because he has been rubbing/scratching it? What is best to treat it or should I just take him to the vets?

Take him to the vets, it must be quite sore now that it is drooping to one side. Ear infections can cause high tempertures etc in dogs also. Best not to leave alone.  Once his ears are 100% better ensure that the hair in the canal is removed regularly if it has not been before this sometimes helps prevent sore ears.

Being honest I would not advice guessing what it is and trying things you have in the house. Double check with the vet first.

Poor Lad. Hope he is better soon. :-)