Okay the mould came off the first pour very nicely.
First photo.
Then I made some front and rear styrene strips and secured them, for between the
two slabs I placed a strip of sticker backing.
Second photo.
Then I poured the second slab.
Third photo.
Now I removed the styrene strips, but the sticker backing paper has partially gotten stuck and gone soft
as well, so I can't remove it.
