Health visitors!!!

In the U.K., can you ignore health visitors? They are such a pain in my back side. Whatever I say or whatever I do with my child is wrong. My baby is 10 week old and he currently has 8oz every 4ish hours sometimes less and apparently at that age they shouldn't be having anymore than between 3-5oz. If my baby is hungry, my baby is hungry!! It doesn't help that my MIL works with her and she is constantly on my back telling me what the health visitor says!! Also when can I start giving him bits of blended food such as rusks etc as well as bottles because the boxes and jars say 4 month but the bloody health visitor says 6 month?!?!