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We measure systemic proper motions for distant dwarf galaxies in the LocalGroup and investigate if these isolated galaxies have ever had an interactionwith the Milky Way or M31. We cross-match photometry of isolated, star forming,dwarf galaxies in the Local Group, taken as part of the {\it Solo} survey, withastrometric measurements from Gaia Data Release 2. We find that NGC 6822, LeoA, IC 1613 and WLM have sufficient supergiants with reliable astrometry toderive proper motions. An additional three galaxies (Leo T, Eridanus 2 andPhoenix) are close enough that their proper motions have already been derivedusing red giant branch stars. Systematic errors in Gaia DR2 are significant forNGC 6822, IC 1613 and WLM. We explore the orbits for these galaxies, andconclude that Phoenix, Leo A and WLM are unlikely to have interacted with theMilky Way or M31, unless these large galaxies are very massive ($\gtrsim 1.6\times 10^{12}\,M_\odot$). We rule out a past interaction of NGC 6822 with M31at $\sim 99.99\%$ confidence, and find there is a $<10$\% chance that NGC 6822has had an interaction with the Milky Way. We examine the likely origins of NGC6822 in the periphery of the young Local Group, and note that a futureinteraction of NGC 6822 with the Milky Way or M31 in the next 4\,Gyrs isessentially ruled out. Our measurements indicate that future Gaia data releaseswill provide good constraints on the interaction history for the majority ofthese galaxies.

Solo dwarfs III: Exploring the orbital origins of isolated Local Group galaxies with Gaia Data Release 2