How wet is the wet wall? For once, the cheapest system is the best, but the wall must be able to dry on the surface.
The damp wall, be it brick, block, or stone, needs filling in of any gaps or holes as you can't treat a hole!
Go to wicks and get plastering sand, cement and rapid cement to fill any wall gaps quickly and help the mix to go off and not stay just wet. read directions on lightening/rapid cement bag. brush in with a brush where it is uneven. Keep the skirting line well filled.
get Wicks blackjack or tanking mix comes in 25 ltrs, get a large course, but decent brush hand sweeping brush will do!
When the wall is dry from cementing/filling, Stir the tanking mix really well from bottom to top. wet the brush first, in water, the coal based mix is water based and brown when wet, but needs turps type solvent to clean you're tools when dry.
Paint the wall reasonably as thick as you can. 1.5 meters up from the floor.
As the dust clogs the brush, wash it out, frequently.
Its dry when black. 3 coats in total and "blind" or "dash" with sand on the last coat for gripping plaster.
Unibond PVA the wall above the 1.5 meters of blackjack when it'sdry and shiny, it's sealed.
Dry line using at least 30mm thermal board and Carlite bonding or drylining adhesive. Wicks is probably cheapest.
Use offcuts 1/2" plasterboard to keep plasterboard from any future damp. carefully remove when set.
All services should be surface so as to preserve the damp prevention.
Skim or joint to finish. Regards rodders