Not all Flymo lawnmowers have the same cutting height. The type of lawnmower and model determines the minimum and maximum height of cut. You should always consider changing the cutting height of your lawnmower when the weather changes.
Raise the height of cut for spring, then lower it down when spring starts to warm up. Raise again if we're lucky enough to get a dry summer, then follow by lowering as the growth begins to pick up in early Autumn. Continue to raise again when you decide to do your last cuts of the year.
Please consult your user manual for instructions on how to change the cutting height of your lawnmower.