John3M
Anyway, I'm looking for a decent submarine kit so any recommendations would be welcome
That's tricky sledding in some ways. Submarines started with very few details at all. Then, got rather "busier" for a bit, to then go very "featureless" in the modern era.
A WWI sub really has few details, perhaps only to one deck gun.
In WWII the need for anti-aircraft protection meant gun mounts sprouted all over the craft. Also, additional sensors were fitted, like radar, RDF, snorkels and the like, along with the need for elevated lookouts, made the periscope shears vastly more complicated as a general rule.
By the 50s, the need for quiet running while submerged menat streamlining all the "fiddly bits" away under cover. This necessitated the use of fiberglass fairings over the metal forms of the conning towers, which brought us the term "sail" for those structures.
As technology marched on, the need for underwater speed, and underwater sleath necessitated removing anything like to create turbulence or the like. So, "features" went away.
And, thus, we can look at the kits with that in mind. A modern nuke (even most of the super-modern diesel-electrics) are simple tubes with a fiddly bit on top, and three-to four fins at the back, and some form of propellor, often in a shorud. So, some of the 1/700 SSNs have barely 6 parts, and the non-hull parts are teenty-tiny. Even at 1/350 SSN & SSBN really do not have high parts counts. The building of those is far more vested in their painting than their assembly.
In WWII boats, with all the "things" on them, 1/350 is really quite tiny for all the wanted "bits." At 1/144, this is improved, but not really by a lot (the selection of kits is higher, though). So, most of the "easiest to detail" kits are at 1/72, but, that's not a large number of kits--and the finished products are a bit intimidating to display. (A 1/72 Gato-Class is more than four feet--1.3m--long when built. Most of the DKM U-boote are right at a meter, and the IJN boats between the two.
So, as with most things in life, there are trade-offs. Details larger than microscope size mean building modeles that eat up shelf space.