Hi Stuart,
When you say wash the walls, I assume that these are painted walls, TEST an area first, some really cheap paints are slapped up in commercial premises, if all ok a neutral cleanser should suffice, hard work though!
Skirtings, I would use the correct amount of Ultra Pac Renovate, yes I know its expensive, in a trigger, spray and leave for a couple of minutes, then wipe off.
Kitchen floor, again Ultra Pac, mop on, leave, use a rotary, then suck up, then rinse with clean water, then depending on type of floor convince client to have it sealed/protected, regards.
Rob