AFAIK there is no service information for any World Lawn product and ordering parts of the IPL is a waste of time as the importers are a mess
The last time I went to the one & only dealer in NSW ( who is an import partner ) with a part number, I had to go back 75km to get the broken cable so they could match it to what they had in stock then wait a week for it to come up from the Melbourne warehouse so that made it 3 x 150 km round trips
The time before I got told the bearings they user are junk and I should pop the seals on all of them & fill the bearing with good quality grease.
So that was it I no longer repair any World Lawn equipment
Because there is no service information, the only wiring diagram is in the owners handbook.
Some have them & some don't
The wiring can change from one year to the next so one year there can be 5 relays and the next year there will only be one and the year after that 3
If you do find a wiring diagram then it will have been drawn by the owners 3 year old daughter & translated into Chinglish by his 6 year old son so it take a bit of working out.
Most times they switch ground because that takes less wire and reduces he number of fuses so it cuts costs
If yours is a one relay job with a 4 pole starter solenoid then it switches the ground from the magneto kill wire ( white or yellow ) in the off position to the starting solenoid ( green or black ) ground
For the purpose of testing only you can get a short jumper with 2 spade terminals on it and then remove the relay
On the plug connect the wire ( marked 30 on the relay ) that is ground ( check with a meter but should be coloured green or black ) to the wire that goes to the starter solenoid , ( 87 or 87a) can be green , black or brown depending upon which colour wire was cheapest on the day they made the looms .
now hit the starter , if all of the other switches are working ( and that is a BIG if ) then the engine should crank & run.
If it does start, note you can not turn it off other than by the fuel solenoid actually working & cutting the fuel supply so the mower is in an unsafe mode to mow with so this is for testing purposes only.
If the engine does not crank then check the Yellow , Orange , Purple wire going to the starting solenoid
It should go + 12V ( well battery voltage ) when your turn the key to start .
If not then one of the switches in the lap bars or the PTO switch is bad
Follow the wires back, bypassing them one at a time till it does crank
If not then the switches are all fine & the wiring itself is shot ( common place )
Both Rover & Parklander rebadge World Lawn mowers for the local market so that might be a potential source for the relay if the relay is actually the problem.