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.
Just wanted to bump this thread, as there is some fab advice on cleaning and restoring.