Railings on Front Boundary Wall

[GlazeAway]

I'd like some advice please. DH and I own our late Victorian mid terraced house after finally clearing the mortgage last year.
One thing we've often liked the look of are the railings that some people in the neighbourhood still have. The house is a Bay and Forecourt style (think Eastenders?). So the front boundary wall is between us and the pavement and the two side walls (maybe 2.5' high) I believe are also ours as they are on our side of the party walls and we're built in the early 90's by the previous owner of this house, who was a builder by trade.
House on one side is owned and the other side is rented.
We'd like them not only for the nice look but also for enhanced security (so our DD can also lock her bike to it, save always coming through the house.
Will we need planning permission? Has anyone done this and had bolt on railings installed and the approx cost?
TIA

The two little sidewalls adjacent to neighbours also match, so obviously same age.

If the total height of the wall and the railing adjacent to the pavement is over 1m (3'3") then planning permission would be required. It is possible that the side walls may too - depends on how far away they are from the pavement. The rule is anything adjacent to the highway in excess of 1m needs PP.

Also: are you in a conservation area? If so, pretty much everything needs to be approved!

No, we're not in a conservation area thankfully. The front wall already has a brick pillar either side, and on the gate side. All topped with a decorative concrete topper (sorry, can't remember the name) the railings would just bridge the gap between the two brick pillars. So they'd be the same height as the pillars, if that makes sense?