The bottom line is, not a single person on this thread, the OP, me, the SWs who have posted, the lecturer in a related field and anyone inbetween is in no position at all to say what the conditions in the house are like or whether the threshold for intervention, at whatever level, would be met.
There seem to be an awful lot of people who have a vested interest in actively deterring the OP from making contact with the LA/NSPCC and the rest of us who have said, "speak with the NSPCC, make the LA aware, and leave it to them. They are the experts."
I think it's interesting that those who have some experience/background/expertise in the area are the ones saying "speak up" and the ones who have know knowledge at all are the ones saying "keep out".
Given that no definitive/irreversible action will be taken on the back of the OP's phone call anyway, I'm not really sure what people's grounds for objection is.
Believe me, there are plenty of referrals that go nowhere; or are not purused following a conversation with the Team Manager; or are closed after an Initial Assessment; are deemed to be malicious; are recorded as an overzealous neighbour as well as those that proceed to CP; end up in LAC...
Given that the mum might benefit from a variety of support services and the children might have their lives improved immeasurably, I'm struggling to see what the objection is beyond some people thinking the OP is "gossipy".
Anyone who has been on any level of safeguarding training knows that you always raise a concern and then leave it to the experts to respond appropriately. You never just turn a blind eye to it.
As I have said, and someone else has said, safeguarding/child protection is everyone's responsibility.