^+1 based on your comment of the leather not being worn.
I'd use a ph neutral cleaner for leather. Try either checking www.detailingworld.co.uk
or the www.ultimatefinish.com
. Both UK based so shipping won't kill you.
I'd suggest if available either Leatherique or Leathermasters but if not available in the UK try Sonus which is for sure. SwissVax is another nice option but pricey, actually the Sonus is cheapest by far so maybe try that first.
After your leather is truly clean, weekly to biweekly wipe downs with a warm slightly damp cloth should be all you need and clean every few months or so depeneding on wear and dye transfer from clothing.