Ok... It isn't hard to do what you need... but maybe it worth getting the painter to cough up for this... just a thought..
You need to clean the floor with LTP grimex... follow the directions on the bottle.. this will clean the dirt and old sealer off...A scrubbing brush will aid.
Then rinse the floor with clean water a couple times to neutralise the cleaner and you must leave it to dry..48 hrs min
Then you need LTP mattstone to seal with... again follow the instructions.. 2 coats is ample for slate.
If you are unsure about any this then maybe we could get a member to come and do this for you..
So it is fixable? Is the lithofin wax off stuff the shop gave me different to grimex?
The decorator is due round here next week and I'll chat to him and see if he will do it. If not, I think it might be better if we got an expert to do it. I couldn't bear it if I tried it myself and made it worse.
Hey.........guys............no need to tearing now,i'm telling you about my experience just use quala system inc,flore chemie or better Flore cleaner and take advice of famous decorater,it might have been helpful for you.