Not quite sure what you mean by a spur but the charging socket terminals should go straight to the battery. Lighting would normally be run from a switched circuit off the battery. Sometimes it is possible to combine the use of lengths of wire to minimise connections and wiring runs but you must obviously avoid a situation where the charger current is going into the live lighting circuit.
Personally I would keep the wiring for both functions separate, less chance of an involuntary short circuit!
Colin