A strange thing happened in August. The Azolla just all upped and died. It had been a major problem during June and July because it grew so quickly and I was having to net out loads every few days. Then at the beginning of August it started to go red and then disappeared while I was on holiday. Maybe it will come back, maybe it won't. I've tested the water and it is fine and all the other plants and animals are OK. The duckweed is growing now but it isn't anything like as invasive which is good. If anyone knows why this was please let me know.
The pond looks great and I am particularly pleased with my seating area. Lots of local wildlife use it to bathe and drink at which was the original point of creating it.