My S1300 will not start ?

My S 1300 will not start, done all the usual , changed petrol, new spark plug new battery, new ignition switch, not sure if the seat switch is ok, do not know how to check this.
After the new battery it started for a few days, then stopped, fiddled around with the seat switch, it then started, managed to cut a large part of my lawn/field, had to stop to move an obstacle , has not started since, what do you think