classic motorcycle forum

Thanks for the thoughts folks.
I am due to visit the local ye olde leather shop, so we might see what they say.

I do have a neatsfoot oil story.
Was in the garage, a good while back, and heard a strange repetitive noise.
Narrowed it down to a giant cricket chomping on an old seat's leather - which have been treated with that stuff
Chewed a fair hole in it - although it wasn't exactly pristine to begin with.
Hmmm !

Some reading:

The photo of AMP366 comes from here https://motorcycletimeline.com/1935-2/ where it was captioned: "Three years after acquiring its first BSA 498cc V-twin for assessment the War Office ordered a lightweight version (hence the undersized fuel tank) but subsequently decided a side-valve single would be more suitable."

Here's a similar model that was for sale (some time ago) https://motorcycles-for-sale.biz/sale.php?id=37628 The model was called the B15 - some interesting comments on "standardisation" that happened on the military models. The tank on the bike in the photo with your grandad is most likely BSA C11; perhaps part of the standardisation process.

Leon

And whats that circular object in front of the engine, below the horn ?

No idea! Guess it could be magneto or generator related, or...

The nearly-vertical front down tube on the frame must be a decent identifying feature, but can't think of what it identifies!

Leon

Also a long time ago I had a paper from the British Museum on leather restoration and conservation. I was surprised at how firmly they were against neatsfoot oil, saddle soap and various other common leather applications. Then again, one of the leather examples they were using was a Roman sandal retrieved from the Thames so seriously old stuff in pretty ropey condition.
I would seek advice from a decent saddlers or leather merchant. Here in Melbourne for example I’d go straight to Leflers the leather merchants. They really know their stuff.

Many years ago I found some old boots of my late grandfathers that had dried up like your toolboxes and an older bike friend said to fill them with cheap vegetable oil from the supermarket. I did this and after a month or so they had swelled and softened up nicely. I left them to drain and filled with absorbent kitchen paper. Left in the summer sun they dried enough to polish with boot polish, and after all that they were too small for me to wear and I gave then to a cousin.