This is Liberty Tana Lawn Romper, with a lined bodice. There is a height size adjustment option with buttons at the back. Sizes 3-6mths up to 18-24mths have poppers at the inner leg for ease of changing.
This Famous print is a Liberty Tana Lawn and it is named after the lake Tana in Sudan. It's constructed from the long stable fibres of Egyptian cotton. This is what gives it the famously soft and luxurious handle.