Concerned about neighbours' dog but not enough reason to call RSPCA?

[CatAndHisKit]

Just wanted to hear from knowledgeable people whether I should alert RSPCA or not - it's probably not enough but I don't know what the current 'standards' are.
There is a young couple in our street who own a dog. Used to leave him on his own in daytime when at work but they usually were back around 5pm (I'm not here every day but from what I've seen). Also I saw them in the summer walking with the dog to shops etc, though haven't seen then walking the dog as such but I don't watch them so not sure on that. That was normal and dog seemed ok.

Now it's changed - it looks like the woman is away or possibly having medical treatment (they had big rows occasionally and she may have MH issues, even police was called - but she is a nice person essentially imo). So the bloke is on his own and comes back late, some days around 8-9, today it must have been after 11pm because he dog has just stopped barking.
So the poor dog is there by himself all day barking and stading by the gate where there is a gap and he can look at passers by and cars which I suppose is a diversion rather than being locked in, but he is always by the gate - I don't know if on the lead or not. Today was one of the worst days whe he started barking on/off from 12pm - we've bveen out and got back to him barking from across the road again, and just stopped now after 11pm (no lights in windows before then). Occasionally he howls for a bit - it's upsetting to hear and how bored and under-exercised is he! He's young, probably about 2yrs old.

He's not underfed or physically abused so I'm not sure RSPCA would step in, but possibly they also just talk to owners rather than take their pets away, just to encourage them to look after animals properly? In our town dogwalkers are not especialy expensive and many advertise - 10 pounds ph maybe some would take 8 for less than an hour. The dog is quite bored and distressed with no company or walks. Even if he is being walked early morning for a short while, being left in one spot pretty much till 9-11pm is really bad for its well-being.
I don't want to talk to the guy / them directly as it's quite a volatile couple and we are not friends and also I don't know why is she away so don't want to impose.

RSPCA website says complain to your council first about the barking, and they’ll get in touch with the RSPCA if they have welfare concerns.

Does the dog have food/water and shelter outside?

thanks, danger.
I wouldn;t know re food/water as the dog is behind a wooden gate and just has a narrow gap to look out of there. I'm sure he's fed and watered as doesn't look undernourished and generally they used to look after him well enough previously as they were present in the house much more. But I can't tell whether he's tied up to the gate or a post or not - don't know about shelter but it looks like he wants to be by the gate as he's even more bored to stay behind it.

I wrote anonymously about a similar situation and a check was done and the owner spoken to but nothing else was done as dog otherwise fed and in good condition. I don't understand why people have dogs if they are not willing to walk them daily and leave them alone for hours on end. Makes me angry. So I think if you are concerned enough to be posting here then yes I would make your concerns known.

exactly, Highland! why get a dogf when you can't even take it out for a decent walk or two a day! So in your case, that dog continued to be treated the same way? that's a shame, and that's why I wasn't sure if it's worth acting on this.