Need a wall built in front garden - bricklayer? Gardener?

[tak1ngchances]

We have a Victorian terraced house in SW London and I need a low wall built outside with a fence/rail on top and a gate. Kind of like the after pictures here but not so fancy pictures

Who would do that kind of job though...a bricklayer? A gardener? Also how much do you think it would cost...I thought about £1k, DH thinks double that.