Which I use to clean my car (apologies for the bad language) seats.. It definitely doesn't leave the leather looking shiny..
Used to use baby wipes and then rob the Wife's tack box for leather care stuff. Now I tend to ride in textiles which are actually a bigger pain to clean!
I got given a tub of Renapur (I think that's spelt correctly) and find it great, cleans and protects in one, but does leave a bit of a shine...
matt soft finish leather will alwasy be difficult to keep clean and insects do most damage! The matt finish will show some shine with age & use anyway Waterproofing it will reduce insect getting stuck and absorbed and would make cleaning much easier (damp/ wet sponge) Have you tried watherproofing silicon spray? or those for suede? Give nikwax a call, they might have a suiatble product
Dunelm leather wipes cleans mine, a lot of supermarkets do leather wipes packaged the same as baby wipes
I actually use car care products on my leathers. Chemical Guys makes a product called "Leather Serum" that works great, never affected colors or printing on my leathers.
Autoglym leather conditioner keeps it soft but does put a sheen on no matter how well you buff off. The leather cleaner does a good day to day job as spray on cleaner and once a season the Autoglym conditioner