We've got an 11 month old Golden Retriever was was originally fed on JWB puppy but his skin was very flakey and irritated and the resultant scratching caused bleeding. Because of this we switched over to Nutro lamb and rice and the skin problem cleared and his coat became lovely and shiney and soft.

Just recently though, our dog's coat feels quite dry wirey and whilst also feeling a little 'greasy'. Would there be recommendations to change his feed or would others feel this may be part of the way his coat may be from time to time?

He's not been introduced to the joys of bathing yet so I thought the first stop might be a trip to the petshop for some suitable shampoo but would any of you have any other suggestions?

Sounds like he might just be growing up and getting his adult fur

As above, probably moulted out his puppy coat and is growing his adult coat.  I always use Exmarid shampoo when bathing my Goldens as it is basically a coal tar shampoo so is kind to skin and coat.

I agree with the other two, this just sounds like his proper adult coat. Golden Retrievers should have a weatherproof, water shedding top coat and a softer undercoat.