Poppy - I tried everything inside and out.
Sheraton wipes & Waitrose organic fragrance free baby wipes to start with and then lots of goes with Woly gel . (I had several goes at the handles with the cornflour & baby shampoo poultice which removed loads of the 'darkness' on the handles although I haven't shown an after pic )
Followed by several goes with Jones the Bootmaker spa lotion & finally Woly Neutra cream and several sprayings in between.
The last coat is the Neutra.
Inside I used Jones the Bootmaker suede cleaner & several goes with very fine sandpaper on a couple of pen marks.
They quoted £70 + vat to replace the handles which in hind sight would have been money well spent.
Although I would still rather have bought one in better condition to start with for the same overall cost.