Wirey coat - diet advice

Juno's coat is has become wirey in patches. It used to be on his thigh, and I thought it was from the way he would sleep.
But it's now on his shoulders, at closer inspection the skin looks red in those areas.
From a quick google search, there's info on adding animal fat to his diet.
He's fed on Arden Grange (adult/large breed). In the mornings he just gets the kibble and a raw carrot. In the evenings I feed him the kibble with raw carrot, broccoli and cauliflower, with a canine sea-kelp supplement mixed in.
2 days a week he gets mackerel in sunflower oil instead of the veg.

I don't eat a lot of meat myself, so there's never that much in the house. Is his diet missing out on animal meat/fat?

Arden Grange, as far as I am aware, is a complete diet so I wouldn't have though feeding that would make him miss out on anything nutritionally if you are feeding the correct amount...
unless of course it just doesnt agree with him?

A lot of people add salmon oil and/or raw eggs to their dogs food on some days. Worth a try?

I managed to scrounge a few scraps off the butcher, I'll try that 1st. If not, I'll give the eggs and oil a go. Thanks.

I can't see with the food you are feeding he would be lacking in nutrients .. I would have him to the vets to rule out any health issues such as cushings / thyroid problems .

Raw organic cold pressed coconut oil is good for coat, skin and many other benefits. Feed a spoon a day and rub it into the red/sore areas. Salmon oil is good too.

That said, I would take my dog to the vets, as you can't properly treat a problem without knowing the cause.

Well, went to the vet today and they couldn't find anything wrong. The vet is happy with the diet he's on and said the rest of his coat is in good condition.
He thinks it was maybe an insect bite that got agitated, and that Juno was scratching/licking it. Have to keep an eye on it for 3-4 weeks.