Again, this is not about "alleging abuse". It's about reporting anything that makes you uncomfortable or uneasy to a senior member of staff and following guidance and procedures. In our case, that would involve discussing all the details that made you uncomfortably with a very highly trained Safeguarding person (usually a very senior nurse) who would advise on next steps. It's not about going in and willy nilly accusing people of abuse. In the first instance, for example, that might just be saying to the mum with the dirty house week in and week out if they are finding it a struggle to get things done, asking a few questions about what support they get etc.. giving them a chance to talk and details of any other services which might be of help e.g. it might come out in the conversation that they were having money troubles and you might tell them you would find out some information for them. What do you need a load of training for that for? Really? It's not about 'getting social services in' to 'check them out'.
Also, if you are going to get social services in, as a person working with a child you have to discuss the referral with the parent, which you would support from a senior member of staff to do. The first time I ever did it, a manager came with me.
Everyone who works with children is expected to know and act in this way. Everyone, regardless of what their official remit is, or their qualifications, or how supportive or otherwise they are expected to be. It is just the way children's services work, and yes, it is serious, and yes, people do miss things.. but what you are suggesting is that "unqualified" people shouldn't come into contact with families, which is the alternative. In which case a lot of services which do a lot of good wouldn't be able to run..
So, take your pick: hear no evil/see no evil/speak no evil or support for vulnerable families that involves an awareness that you need to discuss things that concern you with senior members of staff and may need to report uncomfortable things.