Google earthing it seems to indicate almost 1100m for the ground roll. Now i'd uped the Vr number by 10 kts to get as close to Vy.
This actually sounds right for the conditions and what you were doing. The total take-off distance from the book (unfactored) indicates a little over 1000m required, thats with a TOSS of 69KIAS and clearing a 50ft barrier. Throw in the factors of old aircraft, lazy old engine, couple of bugs on the wing, few knicks out of the prop, actuall weight maybe slightly more than factored.
Increasing your lift off speed by 10 kts is exceeding the correct speed by over 13%, which will dramatically increase your ground roll beyond that considering you are trying to accelerate with ground friction and the gear still extended. Rotating too early does increase take-off distance as well.
The Piper P-Charts for most pipers end at 38C (100F) at sea level, by 2000ft then limit temp is down to 33C. Essendon being at 300ft would put the limit temp around 37C.
Why do i refer to a limit temperature on the Piper charts? Piper has stated in a number of earlier accidents that where the temp lines end marks the environmental limit and performance will degrade substancially from this point and can not be determined safely. If the aircraft is operated beyond these lines it is outside of certified limits. This is also the reason in performance theory you are told that you can interpolate between the lines, but never extrapolate or extend the lines.