I agree with the above poster about the Rab Gloves and would just like to add that I have found having a pair of Buffalo XXXL Mitts as a back up for it being too cold of dropping a glove a God send. They are super warm, light and cheap.
I used these on Mt. Blanc a couple of weeks back and were plenty warm enough. https://www.decathlon.co.uk/cascade-glove-id_8331057.html Which Decathlon gloves did you get? I noticed lot of guides were using those 'yellow' leather gloves - Extreme Technique had loads and Decathlon has a Simond branded pair.
In summer I use a pair of Mountain Equipment Super Alpine gloves and very rarely wish I had anything heavier. Can also second Buffalo Mitts as being a very good choice for 'emergency handwear'. Weigh about as much as a quickdraw, take up no space and are incredibly warm.