Sand, de-dust, varnish - repeat.

Too hot to varnish in the middle of the lawn so I moved it all under the trees.
The sun went round and it was out of the shade after all and the trees dropped loads of junk on the wet varnish followed by dozens of little flies that are now secured by their feet.
This was coat number four and if the rain holds off tomorrow then that could be the last repetition of the process. Hopefully the sanding will remove the foreign bodies!