Never mind the position of the pump head, it was just illustration.
Tubing was bought in a pet store (6mm) and T connector online from eBay.
Drill a 5mm hole in the cap of the carbonated bottle.
Get an old tube and cut out the valve. Hacksaw it in two, use the bottom half in the soda cap. Use the other half in the tubing.
Pump up the bottle to 70PSI safely and then release the clamp holding the tubing over the valve (with core removed). Job done