mojo pixy
...שלא נמצא בשמאל
well .. 'catalan' and 'spanish' may be combined as 'iberian' (and thereby include also portuguese, basque, galicians, gibraltarians etc) but certainly not 'spanish'.It's actually not quite like most of those examples, because I think with all of those examples the smaller group is at least arguably a subcategory of the larger. But "Scottish" is definitively not a subcategory of "English". There's a perfectly usable category that contains both: British.
It's a little bit different with Wales of course, because it's not a real country, but for most purposes we just agree to gloss over that.
'sicilian' certainly isn't the same as 'italian' (any more than 'maltese' is) but we all like our shortcuts.
'british' is fine as far as it goes, being any native of the british Isles (or if you prefer, only natives of the largest island, though this would exclude natives of the thousands of other islands). but most foreigners don't do 'british', they just call us all 'english' (no doubt on account of our lingua franca, as sicilians get called 'italian' when they aren't really)