Nallo 4 GT

Edit: Just read that you're a family of 5. Whoops! sorry. The Hilleberg Nallo 4 GT has been amazing for our family. We've used it all over the US, Alaska and in Northern Europe as a family of 4, and it's basically good as new still. An investment, yes, but if you camp a lot in varying conditions, it's an amazing bit of kit.

The Nallo red label is absolutely considered a 4 season tent and I would not hesitate to use it in the winter under most conditions. Only the black label version would be better for extreme arctic conditions.

Think about the Nallo GT as well, it gives you oodles more space in the porch compared to the Nallo for little weight penalty. I love mine and have used it from windy and rainy Dartmoor to windy and snowy Norway.

Only four season tents retain heat.

Yes but crucially, as I pointed out, **only four season tents**. I’m not sure why you’re persisting in labouring this point when neither of your tents is a four season tent. Furthermore, as many have pointed out, the shape of the tent has nothing to do with any insulation properties, and even then, the insulation is so trivially small that it simply shouldn’t be a consideration in your choice of tent. How about actually listening to what people are saying instead of constantly arguing? 🤷‍♀️

The shape of the tent has no bearing on its warmth; primarily you should be relying on your sleep system for warmth. True four season tents (eg Hilleberg Red and Black Label), regardless of shape, do add a few degrees to the interior, but this is due to the lack of catenary curves in the fly (ie the fly extends all the way to the ground) resulting in less ventilation, and a solid inner as opposed to mesh. I’ve actually measured the difference and found that my four season tents can be up to 5°C warmer inside than outside. **A three season tent will not provide any warmth.** Sure, they may be warm (even uncomfortably so) when pitched on a sunny day, but that warmth will not be retained and will rapidly dissipate after sundown. Ultimately whether you choose a tunnel or a dome is more a matter of practicalities. Tunnels are usually quicker to pitch (ideal for wet weather) and offer the best space to weight ratio. The downside is that they need to be pitched parallel to the wind for minimum flappiness, which can be a problem if the wind changes direction overnight. Domes, on the other hand, allow slightly more flexibility with altering pitch spot since you can usually erect the tent and then find its optimum placement before pegging down. This can be really handy when you’re expecting lumpy ground. So, for me, the factors which determine which tent I’m going to take are the forecast and the expected terrain 🙂

The obvious choice is Hilleberg. The Nallo is a great tent; just pitch it so the vestibule faces into the wind and it’ll take pretty much any conditions that are actually hikeable in the UK. And I see that, with tedious inevitability, people are being downvoted for recommending expensive tents, despite the OP asking specifically about them.

~~Winter camping can mean many things. The Nallo isn't a 4 season tent. Specifically, it isn't adapted to snow. Those cat curves on the lower perimeter of the fly are practically impossible to bury and the spindrift will flood the interior. You will regret using the Nallo in full on winter conditions (blown snow).~~ If you have a very limited budget and need one shelter to do it all, your best bet would be a mid with as many sides as you can get/are willing to carry (i.e., a rectangular pyramid -> a hexagonal mid -> an octagonal mid). Edit: My comments about the cat cut on the fly is due to confusion with the Anjan! My apologies for the confusion! FWIW, I've personally used and owned at different points 3 of what are now called the Black Label tents and 6 of the Red Label tents.

I own a hilleberg and it’s the most competent of the winter tents I tried out. Very suited to Scotland.  Their red label tents should be acceptable for what you are looking for.  I’d also be mindful of the fact that when camping in woodland l, there can be a lot of beaches ready to come clattering down on your fragile canopy, so make sure you risk asses the area before pitching. Weeks of storm damage can be be forced to fall,  by even the lightest wind in our climate. 

Mountain 25 is a good tent used worldwide. If price is no concern then I would definitely suggest going with a Hilleberg black or red label or Mountain Hardwear Trango 2. Any of the three will definitely last a lifetime. I wouldn’t rush though, order a free hilleberg catalog online. They have some amazing tents. I’ve personally camped in a double-poled (yea you can use two poles where one goes on hilleberg) Tarra and saw winds of 80mph. Fabric whipped a bit but sleeping at that level we always bring ear plugs.