Hi all, I have recently purchased a travel cot as it's the only thing little one will sleep in during the day! I purchased a mattress as many people in the reviews had done the same stating the mattress that came with it was very basic. It's one that wraps around the outside of the cot when folded down so is a board with a small amount of padding on. My question is, do I keep this in as it's the baseboard and adds rigidity and stability to the bassinet and pop the mattress on top or do I put just the new mattress in? I've just noticed that the mattress seems to dip a little in the middle with nothing under it as it's just on the hanging mesh of the bassinet insert?