Allak 3

This absolutely. A red or black label hilli is the answer if price is no object. I have an allak 3 and the build on it is so far beyond any other tent I own.  Those zippers are just a joy to use. 

Sounds like a dome is perfect for you. Domes are not necessarily the best in high winds, but you do not have to take care as much about how to pitch it perfectly - unlike tunnel tents or similar constructions. If weight is not your highest priority I think a dome tent is the mostconvenient for Scotland/Scandinavia, especially in exposed locations like mountains and coastal regions. I use Hilleberg Soulo/Allak and Fjällräven. A lot of lightweight tents use a pyramid construction but they can be a bit annoying to set up - in my opinion. People swear by it but I am not convinced for my use cases (northern Europe with chance for torrential rain and wind over days).

Staika is overkill for the UK. Just go with the Allak. Not a big weight saving but it will be fine for anything Scotland can throw at you.

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 🙂

~~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.