You sneaky boy. I will try that but we are sure it is very slowly still dropping and Grant thought it would seal more once a bit of junk had settled too. Level isn't low enough yet to work out if it is just an adge leak or all over.
You asked about the trees earlier. There is one large silk tree overhanging and it does not have a root system that will cause problems. The leaves, when they drop, are very fine so should not clog the filter or make too much mess. Because of the prevailing winds (and anyone who has been here knows we get strong ones here) most of the leaves will be blown away from the pond anyway.