I recently got to try out a bekko bachi on someone i know’s shamisen. and after using it for a bit. and then switching back to my maple one i noticed a very distinct feeling difference. now i really want a bekko one. Any recommendations on where/how i should go about getting one?
Someone in the U.K. proper may be able to direct you - but bekko (that is, Sea Turtle Shell) isn’t allowed to be imported or exported under CITES to many countries (including the U.K., if memory serves).
This heavily limits your ability to source such, since you have to work with the heavily limited stock within the country.
And even then, you’ll be hard pressed to find anyone willing to sell.
I would, instead, recommend that you look into the casein based synthetic options.
I’d be happy to use synthetic stuff too, its more about the flex of it vs the actual material.
Hey there! I’m in the UK and have had tons of bekkou bachi super delicate stuff. Aint worth it in my personal opinion. I prefer Celluloid blade with wood handle. My other half makes them here in the UK. Celluloid pickguard is durable, flexible but not tooo flexible and super drop resistant unlike bekko which will shatter if accidently dropped.
Those seem pretty good, what is the flexibility like compared to say, a maple blade bachi? and where can i actually purchase one? 
Pretty certain i’ve had a maple bachi before was a pretty old one. There isn’t really flexability in any wooden ones i’ve had. Celluloid is quite flexible but not too flexible, I quite like it anyway. Its got 3 layers to it very durable.Not sure if anyone sells celluloid/ pickguard material bachi. Quite easy to make, just trace your current bachi into a sheet of pickguard material or any material for that matter, and then make a wooden handle to go around it.
I can ask my otherhalf if they feel like making one for you not sure what they’d charge. Where’abouts in the UK are you? I’m over in the northwest.
Down in the south. if you can find out how much it’d cost from your partner i would be interested depending on the price. I’ve never worked with celluloid, and i’m also very barebones basics when it comes to carpentry
EDIT: sorry to also add, out of curiosity IF i did make one myself, how would i go about attaching the handle? and how thick would i want the celluloid blade to be?