I was asked to replace the vinyl in a kitchen, which is in an extension. When i took up the vinyl the floor was soaking wet. I left it uncovered for a week to see if it was just some water trapped under the vinyl or if there was rising damp. Every time it rains damp patches for in various places in the floor. My guess is they did not fit a DPM or the DPM has failed.

Question is what to do now?
I doubt the option of taking up the floor to fit a DPM will get the go-ahead.
Can I fit a floating floor over the top, with a DPM under the floating floor? I worry that the damp could start stinking after a while if it is trapped under the DPM. Also with that option I would have to remove the kitchen and re-fit it.

Open to suggestions...

Synthaprufe?  Mind you the floor needs to be as dry as possible which given our crap summer could take a while. <sigh> when will it stop f*****g raining?

The house is an end of terrace, Victorian (I guess not being from around this part of the world, I can tell you which tribal style a mud hut is built in  ). It is bare brick.
The extension is 6m long x 3m wide (all kitchen), also bare brick, to match the house. It looks like a screed floor but not sure, I have not tried to drill it.
Old vinyl was laid straight onto the bare floor and was not stuck down.
Any more info required squire?

I think I have photo of the floor somewhere I will post it if I find it...

Leaky underfloor pipes are the most common cause of floor dampness in my experience.