If my child will be a UK citizen but will come into the country with my wife (spouse visa) does my child have to be counted as a dependent?

I recently returned to the UK on my own (I'm a British National) with my and child still in another country. Its of course the highest priority that they come over too. It seems you have to pay immigration solicitors in order to do the application. It all seems very overwhelming.

Im very worried that its going to be really complicated and a lengthy process.