DPC / DPM - Internal Plaster bridging question

[SouthDrive]

Hi - I'm getting ready to lay some self levelling compound in the downstairs kitchen and hall area of my 1950s house in preparation to tile it. Ive lifted the old marley tiles and removed the skirting, the old plaster and scratch coat (sand and cement?) used to extend all the way to the floor - possibly breaching the DPC. and so I've cut this back (I'm not entirely sure this was necessary but I got a damp-ish smell when removing the skirting, even after our long hot summer.

Q1 How should I prepare the junction between the concrete floor and the walls? -
Q2 what do I put in the gap between the floor and the plaster?

thanks
Will