Good Morning bernieduffyd524,
Thank you for your question.
In regards to slats we always advise that our own mattresses are fine to go on to a slatted base as long as the gaps are no bigger than 3″.
The reason for this is that the mattresses will attempt to settle between those gaps; This in turn will cause indentation and damage.
If you believe that it is the bed base causing this issue then you could simply buy some sheets of MDF to place over the slats.
This will stop any settlement between the gaps and also firm up the mattress overall.
I hope that this has answered your questions fully but if you do have any further queries then please don’t hesitate to contact the office on 0161 437 4419.
Kind Regards, Lee.