Slating a roof with stepped eaves

Hi, all!

I'm extending a listed building and the permissions calls for a slate roof with cottage eaves. It is an L-shaped plan, which creates higher eaves where the building tapers down.
I just started slating and realised an issue where two sides of the roof join. Because of the tilting fillet and a vent, the eave course sits proud, which creates a gap as in the attached picture.
I have spoken to a roofing merchant but they can't think of an off-the-shelf solution and recommend hacks, like chamfering etc.

Has anyone seen/done anything like this, please?

Note: Ignore the lack of bond. I've just nailed full slates to see how this pans out.

Thanks!

On the lower section of the roof, put a bigger kick on the first course, pack the baton with scraps of lead to gain height.
Grading your slates will also help.

Thanks!
I have graded the slates. I selected the thickest for the bottom courses.
Before calling it a day yesterday I literally had the same idea you suggested, but because there is about 500mm of the lower roof, to match the kick from the upper section would require more than 30mm packing at the lower eave. So I decided to go the other way round: shaving some 8-10mm of tilting fillet on the higher section to match the angle.
I'm removing the fillet now and will report back later on.

simply cut the slate and use a soaker under the cut to weather the bond . easy

I have already trimmed the fillet to match the angles. The fillet is a bit thin, but it seems to have worked. I started slating from the far verge and will see tomorrow how this pans out.
I bought lead and was thinking of adding a soaker, like you are suggesting, but I wasn't sure how to go about doing that. Unless my understanding of the solution is incorrect, it would take at least 3 courses of half slates before the angles would match to allow a full slate. On the other hand, I may be overthinking