I've done it. Took all the threads out and started again threading the heddles on a total of 10 shafts this time!
First I folded the front up again so that I had easy access to the heddles.
Once it was all threaded through the heddles, I could pick up the bundles that I had made and started to thread through the reed.
All I had to do now was to tie-on to the loom.
I use a very strong piece of yarn, about 6x the width of the weaving.