I think that many routes are not based on cardinal directions.
Indeed! I'd go further and say all routes are not based on cardinal directions. Cardinal directions are the basis for nothing here. Other than describing junctions, or parts of towns, I don't believe cardinal directions are used at all in Poland for navigating.
that's what I thought is our way to go.
Cardinal directions and grid systems it's an imposition from the US way of doing stuff that I got Tim (of all people) to realise doesn't necessarily apply to Europe.
Some oddities according to my logic:
DW103 is WE but DW105 is EW
DW107 is NS but DW109/DW110 are SN
DW117 is SN but DW118 is NS
This is useful information. Previously you just said "reverse this route" with one route and I looked and went, nah, that puts the route backwards.
Out of these three oddities, I've flipped DW105 (for consistency, though the flow is arguably from the main road, all the other routes, including the main road, are WE), DW107 (because it is clearly from the main road to the small village).
DW117 and DW118 flow from the lower numbered road to the higher numbered road - which is probably how most routes have ended up as. I've flipped DW118, so at least this pair of routes are consistent with each other, even if DW118 is inconsistent with the other stuff.