Below is a list of all the suppliers who I have found that will ship to the UK, or are UK-based for bento boxes and accessories.
Not on the high street
Urban Outfitters
Marks and Spencer
Squeaky Bee
Asda
Muji
Artbox
Paperchase
Gifted Penguin
The Holding Company
Japan Centre
Tokyo Jazz Panda
Ebay
Dot Com Gift Shop
Casa Bento
Bento and Co (Now available in English!)
J List
Girls travel club – 1 bento box in stock
Lakeland Limited – for lock and lock
QVC – for lock and lock
Foodnut Australia – Lock and Lock Lunch Kits
Fabulicious – For thermal lunch bags
Amazon UK for lunch boxes and bags (Amazon are now UK supplier for Laptop Lunches)
Modes 4 U
Japanese Kitchen For decorative laquerware bento boxes
All things for Sale – bento section
Dino Direct – free world wide shipping!
My Friendly Lunchbox – UK based supplier for BPA free lunch goodies
For Micom Fuzzy Logic Rice Cookers, I have found two suppliers for the UK
Yum Asia – Zojirushi Stockist
Cook Japan – Own Branded and Sanyo Cookers
My Place 
Hello, thankyou for sharing your list of bento finds,
I am currently running a small blog about all the bento gear I find in the UK.
I live in the north east so far away from the major cities so it’s hard to find bento stuff but when I do I update my blog so that you can find them too 🙂
Here is my blog I hope it helps 🙂
http://oh-bento.tumblr.com/
Great to see another bento enthusiast in the uk!
Please check out my blog for other great bento finds 🙂