Hi Martin,
first of all, welcome to BF!
While I am a proponent of not taking alpha glass on some travels for various reasons, trekking in Switzerland would be a location where I would gladly take the teutonic trinity (and maybe an expensive watch too, preferably swiss ;-)
But of course 400 quid is a budget where sth reasonable can be found - since you are going to lug the bins around I would probably aim for a pair of 8x30 or so. 8 times since 10x bins can be difficult to hold steady for some - more so if you're still catching your breath from ascending a few hundred meters.
One important question is whether you're going to wear glasses while using the bins - some are less suited for that due to not enough eye relief. Usually 18mm or more is ok, some people can get away with 15mm - depending on prescription and frame model.
Regarding close focus - this is limited in conventional bins due to the distance of the objective lenses from each other to 1.5m or thereabouts. Some pairs can focus closer (like my Pentax 8x32 ED which reaches focus for me at 1m) but only one barrel can be used - with both eyes open the images will not merge.
There is one model of pocket bins from Pentax/Ricoh, the Papiilio II in either 6.5x21 or 8.5x21, which uses a reverse porro configuration paired with some clever mechanics which moves the objectives closer together for close up views to reach a binocular close focus of about 50cm. It is also small and light, and works ok for distant stuff. Since it is also a pair of (slightly oversized) pocket bins, the field of view is not very wide and the eye relief is 15mm only (so marginal with glasses).
But still, if watching bugs or flowers up close is the main use, it might be a good travel companion - it's also fairly inexpensive. I like the 6.5x21 version better (I had both side by side at some point, gave both away and now have the 6.5x version again) - less narrow field of view and the exit pupil is not so tiny, which makes it brighter and the eye placement is less finicky.
Otherwise a good midrange pair of 8x30 or so will be fine - the Nikon M7 or it's Kamakura brethren from Maven or Kite are well inside your budget and good value for the money, if you manage to find a discontinued pair of Pentax 8x32 ED for cheap (mine was 218 euro for an open box display unit of a discontinued 1000€ pair of bins - I like them a lot as a backup/loaner pair - nice view, rugged and waterproof and ok ER), that would be a steal and of course Opticron has so many nice bins which unfortunately are nowhere to be tried on the continent, so I don't know a lot about them.
Or you could try to find some used bins from the 1000 euro and up range inside your budget - Leica 8x32 BA/BN, Zeiss Conquest 8x32 (not the old 8x30!), Meopta B1 8x32, Nikon HG-L or (with luck) even EDG in 8x32 come to mind...
Joachim
