No problem, it's only dampness in the screed left behind during the curing process. The piece of ply will in no way spoil the floor, once it has fully cured. Keeping moisture in floor screeds/concrete etc for as long as possible makes for a stronger job anyway.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local