Thanks.
I'll download the images in case I need them
I'm actually undecided now about whether I should switch to Lineage.
My primary reason to swicth to Lineage, now that an official version is available, was because the local COVID check-in App required by the government would not run on GrapheneOs.
However, I managed to fix the problem by installing MicroG Core Services, via Froid.
I also just read that GrapheneOS plan to add a dummy GooglePlayServices App, with no special permissions, which reports that the Google servers are offline, which would do the job of MicroG
However until that feature is added, it looks like MicroG is a good alternative.
Also, the AroraStore app seems to be mostly working, so I can get Apps from the PlayStore directly, and don't have to sideload etc.
Prior to installing MicroG, I noticed a some Apps would not run on GrapheneOS, but I'm hoping that now I've got MicroG installed more may work.