Help Needed!- Fetcher Dog are in urgent need of a ride on lawnmower, any suggestions?

Our ride on lawnmower has given up and we need to find another one in the next couple of weeks before the grass in our fields starts to get too long and can no longer be cut without us hiring someone with a massive cutter.
Our dogs go out in the fields every day and the longer the grass, the more at risk of tick bites etc they are are.