The garden size justifies a petrol mower and a rear roller self propelled would be best also stick to a good make ie Hayter or Honda. Up north said to tip it on its side, this should never be done as oil and fuel can contaminate the air filter or fill up the exhaust, the only way to access the under side is to tip it rearwards--handles down to the ground and all ways remove the spark plug cap for safety reasons.
To explain how the roller helps - If you have inch wide big wheel at one end, thin axle between and inch wide big wheel at the other end, you only need to go past the edge of the lawn by that inch for the mower to fall onto the garden. A roller is like having a big wheel the entire width of the mower. You would need to have more than half the width of the mower past the edge of the lawn before it would tip. The roller also spreads the load of the mower weight and puts less pressure on the lawn edge so it is also less likely to cause the edge to collapse.
Yeah i agree with you that the lawn mower depends on the size of garden. I will also suggest that you should also keep the lawn mower repair manual so that you might be able to repair it all by yourself.
Posts
Up north said to tip it on its side, this should never be done as oil and fuel can contaminate the air filter or fill up the exhaust, the only way to access the under side is to tip it rearwards--handles down to the ground and all ways remove the spark plug cap for safety reasons.