Short answer
The gas hose leaves a grill on one side only, and that side decides where the cylinder cabinet goes. Decide it at the ordering stage: once the modules are bolted in sequence and the fascia is cut, moving the entry side means re-cutting a finished panel.
Where to look
On a built-in grill, the gas inlet is a threaded connection on the underside or the rear of the chassis, usually offset to one side. The installation manual shows which side in the plan view.
If the grill is already in your possession, look under it. The inlet is a visible fitting, and on most models the regulator is already attached to it.
What the side decides
Two things. Which end of the run the cylinder cabinet goes on, and whether the hose travels inside the run or around the outside of it.
Inside is neater and better protected, but it means the hose passes through or behind a neighbouring module. Outside is simpler and shorter, but it is exposed. Neither is wrong; the side has to be chosen either way.
Why it cannot be changed later
The fascia slots, the opening and the gas entry cut are all made in the same operation at the factory, and the panel is edge-finished afterwards. Drilling a new entry on site exposes bare core at the cut edge, which is exactly where corrosion starts outdoors.
The reverse side is not a mirror. A grill cabinet is not handed in the way a door cabinet is; the entry position is a manufacturing decision, not an assembly one.
If you do not know the grill yet
Say so. Where the grill model is still open, we specify the entry on the side that keeps the cylinder cabinet at the end of the run — which is the most flexible arrangement, because it can serve either a left-handed or a right-handed grill later.
If the grill arrives with the entry on the other side, the hose runs outside the run rather than inside. It works, it is just less tidy.
How to settle the gas side in four steps
Follow the hose, not the knob
The gas entry is where the hose leaves the appliance body, which is not always the side the controls are on. Look at the back of the unit.
Note where the regulator sits
A regulator hanging outside the appliance body needs room inside the bay. That space has to be on the same side as the entry.
Put the bottle on that side
The gas cabinet, or the space inside the grill cabinet, follows the entry. Crossing the hose behind the appliance is what gets refused at inspection.
Decide before the modules are bolted
Once a run is bolted and the counter is set, changing the side means rebuilding the run. It is a drawing-stage decision, and it is free at that point.
Questions we get about this
Can the entry go on the back instead of a side?
On a wall run, yes, and it is often neater. Where the run backs onto a wall the entry can exit rearward into the cavity behind the cabinet line. Tell us at order stage.
Does the side affect the gas certificate?
Local gas regulations set what the installer must do, and they are about the appliance connection, not the cabinet. The cabinet gives a clean entry point; the licensed work is the regulator, the pressure test and the hose.
What if there are two grills?
Each needs its own entry, and both usually share one supply on a tee. Your fitter decides the tee position based on pressure and hose length.
Before you order anything
Send the grill model and the run length. You get the aperture, the module list and one itemised price back in writing — freight shown separately, valid 15 days.