Rising Damp - internal wall and concrete floor

[Naomi]

Help!

I think we have some rising damp. The plaster is flaking and bubbling and there is a yellowy chalky deposit above the skirting. The area is a section of wall about 1m long and the marking on the plaster rises to about 1m

This is on an internal wall. The wooden floor sits on joists which sit directly onto a concrete slab floor.

The house is 1860's and does not have a DPC, but does have a DPM as I understand it.

Can anyone come up with some advice??? I seem to be finding it impossible to get anyone round to have a look at it.

Thanks!

Naomi