The XL might be big enough DewDrOp if your children are still small. You might be able to fit all three of them in one bedroom and the two of you in the other (as the pods are 160cm wide which would accommodate a king size (5ft) airbed).
As they grow you might want something bigger, but at the price they are now they might be worth it for weekends. Also as children do get older, they often want their own little tent anyway.
You can buy extra living space in the form of their Base Seconds pop ups but obvously that adds extra expense and you have to link them in some way (I guess the Decathlon staff would know how to do that).
I really like the look of these but can't work out if they would accommodate five of us? Dh and I both get a bit claustrophobic so like a reasonable amount of sleeping space plus obv need room for 3 dcs...
..now is the time to do it. I have just been on their website and they are still selling the old version Seconds Family 4.2 and 4.2XL for £119.99 and £159.99 respectively. The new versions (which are more attractive and a bit higher in the living section) are £219.99 and £269.99 respectively. Unless you need the extra height, this has to be the time to bag a bit of a bargain.
I would go for it but we are already tentastic in our house and have just got the Base Seconds XL (or whatever it is called) as extra living space, so I really can't justify it, can I????