mirtzapine There is so much inaccuracy in that post I am not really sure where to begin.
OP if, after the visit, there are concerns, the next courseof action will depend on what those concerns are. If they feel you need some support for some reason, you may be referred on to Early Help services. Your child might become subject to a CAF which is anassessment which allows different agencies to work together to help families. You may get a family support worker or type of support worker depending onthe issues.
if the concerns are more serious, you may be referred for an assessment. Depending on your local authority, this may or may not be called an 'initial' assessment as they are being phased out. If after the assessment, there are still concerns, your child may become subject to a Child in Need (CiN) plan. This is quite low level and will be about putting support in place similar to a CAF but led by SS and maybe with services paid for by SS. CiN plans do not usually have conferences. To put CiN into context, all children known to social services are classed as CiN including disabled children who received respite or other services.
if the concerns are more substantial then Child Protection concerns may be raised. If this is the case then an Initial Child Protection Conference will be called with a independant chair and a team of relevant professionals. If the conference decides that your child needs to be on a Child Protection Plan then one will be put in place - the child protection register has not existed for some years now.
Unless your child is deemed to be at immediate or serious risk of harm OR whatever measures are put in place via the plan deem not to be working your child will not be taken into care.
There are no time limits for how long a child can be CiN or CP. CiN plans are reviewed every three months and if a child is still on a CP plan after 15 months then it will be looked at more closely to see if it is working, although the plan is actually reviewed every 6 weeks to three months. At any point in the process things can be de-escalated for example CP to CiN or CAF and CiN to CAF.
However, on saying all of that I would also think, given the wrong address is on the letter it isn't actually for you. If it is for you, the fact that they have written to you rather than visited would suggest that the concerns are not that serious.