OP- if you are not happy for your 2 year old to be seen, simply decline. There is little point in cross questioning the HV as to why she is seeing your DC. It is simply a routine contact.
near- you obviously had a v disappointing experience with your HV. However, some of your posts make you come across as unreasonable in your expectations (expecting the HV to be the one person who supported you in the newborn period) and others patronising, rude and unpleasant:
'Well then jakebullet duckie - as you clearly want to plumb those sorts of depths, that's precisely what you shoukd have been doing. Not, as my little HV got her kicks from, trying to degrade women who were clearly doing their best in a loving environment. I didn"t want her in my home without an appointment at 9am in the morning wly hen my baby was less than two weeks old spouting ill informed crap - bt it was clearly a nicer place for her to be than a dirty flat, 22 floors up, where she was needed.
At about that time the chairman of the HV association said in the broadsheet press that the role of the Hv was to teach ignorant mothers the three Cs - "cooking, cleaning and communication". Nothing much more rude than that imo and anyone who lumps me into that can take a running little jump and that alone convinced me that I would never deal with your smug little profession again.
As you were duckie!'
Obviously you didn't receive the support that you needed, which is poor and disappointing for you, but perhaps, from the HV's perspective, you were more difficult to help/ form a relationship with than the majority of women that she saw. The above post certainly makes you sound v difficult to me.
I'm not a HV in case you were wondering.