IO540 has left out what for our group is the most expensive item - hangarage.
...and landing fees!
The 'real' cost of the aeroplane (PFA taildragger) is around £50 per hour; roughly £20 fuel, £10 landing fees and £20 for hangarage, insurance and maintenance. Operating off a farmstrip rather than a licenced aerodrome would probably knock £20/ph off the costs.