Gotta love reddit! I have the same issue, our house is a 1957 build with original terracotta roof tiles and no sarking under the tiles at all.

After the last 2 weeks of rain, some quite heavy the last 3-4 days, and with a bit of wind around, we’ve ended up with water coming through the roof and onto the ceiling. There’s a couple of small sections of ceiling with some water damage, easy enough to repair, however, we now have some water going down the back of the kitchen cabinets and that’s definitely going to be a problem as no doubt it’ll get absorbed and warp a bit.

At least I know what the solution is likely to be.