Bingo!
Thank you so much it had been bugging me
Am smiling now.
The leather is actually Oak, although Congo seemed to ring a bell.
If you look on this link for ebay tinyurl.com/n87eypu there are internal photos too.
Being completely honest, the leather is brilliant quality. I've never covered it in the rain and only polished about three times over the years. It's the best bag I've ever had.
Second best is an Anya Hindmarch, which has lots of good features, especially the internal clip for your keyring, but is a bit too huge for daily use.
But that's not the point of the thread, sorry 
I think Mulberry have suffered since being sold, buying into the hype of the 'statement' bag and the belief that they're in the market for people who absolutely must have each season's new design.
I don't see them in that niche at all. Rather a really good staple that becomes like an old friend. Smart, functional and dependable. That's where I think they ought to be positioned really. Something that would sell well worldwide off the back of being quintessentially British rather than being at the whim of fashionistas.