Is it safe to have a gas stove on the same circuit as a couple lights
It's only necessary that electric stoves (ovens in the UK) have their own circuit. This is because they draw more current (30A in the UK) than a lighting or power circuit.

It's OK to have a gas oven plugged into a normal mains circuit as they only use electricity for:


The clock/timer
Lights in the ovens
The ignition circuit


None of these are heavy load, so can be safely accommodated on a standard circuit.

The same rules about not overloading a circuit apply of course, so check what else is on this one as well as the cooker.