Hi to all. Following previous recommendations iv'e bought a new clarke and a bottle of argoshield light to use on my car. I'm not sure about setting up the regulator that comes supplied. It is a single gauge reading in bar and psi. Any advice appreciated.
Welcome to the forum. The gauge on that regulator just measures bottle pressure. You need to judge the flow rate by ear.
Open up the bottle valve, hold the torch trigger down, and adjust the flow rate by screwing the plastic cap one way or the other until you have hear a decent hiss coming. That'll be a good starting point. You might be able to turn it down a little without affecting the weld quality - bubbles in the weld and a brown (rust) covering on or close to the weld would mean too little gas flow.
Turn the bottle valve off after welding - the gas valves inside the welder/torch can be leaky. Mine was bad and I lost half a bottle of gas over a weekend.