Finished the initial build (basic kit + power pack + heated bed + TMC2208's) and have had good results from initial prints.
After build / config and installing the Octoprint there is odd behaviour.
When you start a print (from Octoprint or from the control screen on the printer) if Octoprint is powered on then both X & Y axis try to move beyond their maximum limits, the Z axis goes too low and if printing does start it's at least twice the size of what was expected. This is only fixed by turning Octoprint off before starting to print.
Also, I think it has been noted on the forum before, the supplied power adapter for the Raspberry Pi does not supply sufficient current for a Pi model 3B+ to operate. I have had to connect to a separate power supply (this makes it easier to switch it off!)
Any help would be appreciated - I'd also suggest turning off the Octoprint module if you are having issues on first prints / homing etc. until you have the printer working well without it.