Peter, I am curious; how do you wash it and how does it affect the leather? If I recall correctly, the instructions advise against washing.
Anyway, my Hadley pro is 5 years old so it shows only very little signs of use.
I cant recall what the instructions say about cleaning.
But I use a high grade wool wash (liquid - not powder) - I prefer one with eucalyptus oil in it. I find it works perfectly, perhaps because of the slight oil content - eucalyptus oil particularly seems compatible with leather and is widely used in Australia anyway for cleaning natural products like cotton or wool (and in my case leather).
The technique is to fill the bag with cloth (I use old towels) till it's tight. I mix an appropriate amount of wool wash with warm water and sponge it on without getting the sponge too wet - you do not want the bag to be saturated through completely - only the dirty exterior layer.
For any tough stains I use something like a soft nailbrush to remove the stain. This usually works but some stains seem more resilient than others. I also find it more effective to go over the entire bag exterior otherwise if you spot clean after drying you can be left with dirt rings around spots you have washed.
Then I swap the wash water over with clean warm water and go over the bag once more to rinse out the residual soap / wash solution.
Finally, I leave the towel-stuffed bag to dry slowly by hanging it up somewhere (e.g. like using the strap on a door handle) in a spare room or laundry where its not too hot or cold. Takes maybe 24 hours plus minus to become dry depending on ambient conditions. For the last bit I remove the towels so the interior gets a chance to dry perfectly too. (You may wnat to make sure its totally dry by leaving it a few days more before putting expensive camera gear in it.)
The idea of stuffing the bag is to help it retain its shape. Also its easier to handle this way when washing. This works, believe me I have done it half a dozen times and it keeps my Hadley bag looking pretty much new. I am not sure about the older bags which judging by my older bag uses different fabrics. It works here (I have tried it) but perhaps not so well.
Never apply heat to dry it when drying. This is particularly important for any leather - leather that is saturated and dried in heat often becomes hard and brittle. My technique works well and I have never had any problems. If worried you can carefully rub a little leather conditioner into the leather trim.I have done this using an oil painters artists brush with a flat cross section as its easier to control so as to avoid getting the oily leather condiitoner on the bag fabric.
Much harder to describe than to do, its easy and I as I say seems to work perfectly causing no damage to the bag or trim.