My dd barely crawled, cruised when she was well over a year and didn't walk independently til she was 16 months. She too was happy sitting so long as she had plenty of toys nearby, or would sometimes move about by rolling, commando crawling or a variety of wierd and wonderful methods. She too was advanced in the more cerebral activities, talking very early.
She's now 6 and perfectly okay at walking, running, jumping etc, but still has an above age ability with talking reading, writing etc.
Give it a bit more time and she'll probably develop perfectly well at her own pace. Milestones are helpful, but can sometimes be worrying if your child is a bit slower than the textbooks say. Remember they are average ages, so some will be sooner and some later. If you're still unhappy in a month or 2 I'd see the HV again.
HTH