Teddy, it was never a issue of being overweight. The weight issue was bought forward as it being an issue of not having enough performance in getting out of that strip in the runway available. There is also a escape route to the right of the runway if needed. IE getting behind the drag curve.
As for flying ham's question.
I can remember the temperature of the day was around 32 degrees. Give or take a few degrees. Peak of the day was 36 degrees. It was not that at that time of the day.
The QNH I cannot remember. But a web search shows the QNH of around 1015. It usually drops during the day by one or so each hour after 10am.
My estimate puts the planes weight at 8020lbs. 32 Degrees, say a QNH of around 1011, with approximately 5kts of headwind.
A quick guess would put that at around 680-700m for a 50ft barrier?