Thanks for the quick response,
the problem is there is no where for me to enter an ip address.
When I run flotilla the browser opens and I have "input with a + on the left, modify in the centre, output on the right with a + and the anchor in the middle at the bottom".
As the browser opens it looks like it attempts to open another box, (possibly the box to enter IP address) but nothing is displayed.
If I click on the anchor sign at the bottom and then the dock icon, nothing happens. So there is nowhere for me to enter an IP address.
The browser is pointing at 127.0.0.1:8000
If I then close the browser, connect to the internet and restart flotilla I get a box with searching for docks displayed, with my dock listed. Also an option to find dock manually.
I can then connect to my dock, disconnect from the internet and it works.
So, as I am using a PI3, a work around for me would be to connect to the internet via my phone, find the dock and then disable wifi.