Mattress fitting with 6th seat in place

[Jlr1]

Hi, I'm running a Beach with the 3 seat bench and one additional 2nd row seat. I'm just about to get a Venessa mattress and wanted to know if I can use it easily with the 6th seat laid flat? Presumably I'll have nothing under the mattress on the drivers side 2nd row? Is anyone using a similar set up?