Update!
I was up and about at 4am. All the fluffy humbugs had survived the night OK.
Parent ducks arrived in the larger side garden at around 4.30. For 30 mins I let them settle/ call to the duckies in the enclosed rear garden, then I opened the joining garden door. Last night I had left that door unlocked and just held in place by a couple of bricks and with a rope attached to the handle and through the house patio door - so I could gently pull the garden door open without going outside and causing a disturbance.
There was a family reunion in the side garden then they all started to move off through other gardens initially then out onto the pavement. Within 50 yards there were 2 parents leading 6 chicks - but there were 8 chicks leaving my garden. I still have not found the mising 2.
Parents and 6 chicks were "escorted" down 2 roads, across a normally busy main road and then into a small housing estate that is next to some allotments/ a playing field and then a nature reserve. By 'ek, they can't half run those little 'uns. I finally 'lost' them when they went under a back door into a garden that backs onto the playing field. Being only 5.15 am at this time I did not think the occupiers would appreciate being woken to ask "can I check my duckies are OK". One parent flew off at this time - I think I was getting a bit too close.
OK, so that lot are probably OK and will all make it to the nature reserve -
what about the 2 who have gone AWOL? No idea. I have search my garden and they are definitely not there and yet I know 8 left the back garden and there were only 6 with the parents some 50 yards later. More searches after I have had some rather early breakfast.