"Broadback" wrote...
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?

If your weather has been anything like ours, it hasn't stopped raining
recently topping up our pond in the process, it's very likely you have
leak.

If it's a concrete pond frost can do that and you may have to empty it to
find the problem/crack, possibly put a liner in. If it's a liner pond then
let the water drop and where it stops dropping you will find the leak,
normally where some animal has clawed it's way out, there are patches for
liners.

--
Regards
Bob Hobden
W.of London. UK