UKC

Next week I will move onto a farm for a few weeks. I'll be sleeping in a family sized tent. I want to be comfy and my Sea to Summit Ultralight mat is fine for a weekend (5cm deep) but I'd like something at least 7.5cm deep and wider than 55cm ideally. 

Alpkit dozer (or double dozer for ultimate comfort) - if they're in stock.

Go to Millets and buy a cheap airbed and pump for around a tenner? Massive thickness to soak up any uneven ground, it's what we use for family camping and been good for us.

Vango Comfort 10.

Big, bulky, but as comfortable as my bed.

I've got a Thermarest Topo Luxe Extra Large (10 cm thick, 76 cm wide, R-value of 3.7, weights 960g). Comfortable but pricey!

Cheap memory foam mattress cut down from Ikea. We use one in the van and it's amazing.

I guess it comes down to cost and future use intentions. If it’s something you will want to use again for car camping then the thicker Exped or Robens mats are probably the answer(more expensive).

https://www.trekitt.co.uk/sleep--and--shelter/sleeping-mats/self-inflating-...

If the intention to be just for this (then punted on), I’d go for a single memory foam mattress or mattress topper. 

Alpkit Dumo! 

Karimat mate. Brilliant 

the smaller the better

Comfort Plus Mat - Sea to Summit

Very comfy, but also quite heavy, double layered too so redundancy if one side gets a puncture. 

Cheap air bed. Cost about £20 and are about 12 inch thick. Very comfortable and if you put a duvet underneath you as well as one on top it massively increases the warmth.