In article ,
Charlie Pridham wrote:

I had to do similar about 20 years ago, we emptied and cleaned out the
pond, left the old liner in, re lined with old carpet from the dump
(guys there thought we were nuts I think!) then new Butyl liner, we did
it in August

Ah great Charlie - just what I wanted to hear! Someone who's got
(exactly the same) T-Shirt! I will proceed with this plan in August!

John