Source of the River Aire.
On one of the pictures you can see the river. This leads to sing holes and later rises at Malham springs which continues to the River Aire.
Malham Tarn Location
NOTE: This is National Trust land, so you are not allowed to take off from here.
If you check this map: NT Map then you will see some not NT land just under 500m away at the North East of the lake... a bit of a pain but looks like you can set off from here an walk with the drone to get closer.
PLEASE CHECK FOR YOURSELF - DO NOT TAKE MY WORD FOR THIS.