Thanks for all your replies.
I was able to check the moisture in the floor (using a friends hygrometer) and approximately 90% of the readings came back below 75% RH. There were a couple of "spots" which had readings over 80% but literally moving the hygrometer a couple of millimetres away...
I have a bit of a situation at the moment whereby I was due to have some Amtico laid for me a few weeks ago. Having spent months trying to locate a fitter, the agreed date finally came around. However, for one reason or another, the fitter wasn't able to lay the flooring during the agreed time...