In message , Broadback
writes
Since the cold weather freezing the water my pond level has dropped
substantially. Is that likely to be natural or has it developed a leak?

Does it have a pump and a filter? If so, the tank that the water pumps
through may be clogged up with muck and need cleaning. If that happens,
the water can't get through the silt and comes out of the top of the
tank very quickly indeed. The tank may look OK when you lift the lid
and you may not have noticed the water running out of the top. If you
have sponges in the tank, they will need cleaning with water before
replacing in the tank. (A messy but rewarding job). If you have koi,
you must then add the appropriate chemicals to get rid of the chlorine.
(Sorry if someone else has said this - I have only just seen your post
and answered immediately as I have to go and cook now).
--
June Hughes