I just spent half a day trying to find an online retailer in the U.K. to buy the TB50 batteries. Many places list them as in stock but will admit they are on back order when telephoned.
If it helps any other U.K. or E.U. pilots I managed to buy 3 pairs (can be flown with one battery but matched pairs best) from the link below.

https://www.coptrz.com/inspire-tb47-battery-4500mah-178.html

(Yes I know it says TB47 not TB50 but it's the correct batteries, just the link text is wrong).

I will have a few in stock Friday...so if anyone needs please PM me. UK based.

Now in stock: http://robinuav.co.uk/products/dji-inspire-2-battery-pack

Robin UAV Posted at 2017-1-18 04:45
Now in stock: http://robinuav.co.uk/products/dji-inspire-2-battery-pack

Hi do you have a X5S Camera without the lenses and where are you based??

Cheers

Tony

Hi Tony,

Yes I do, I'm based in Sevenoaks, Kent.
See it here: http://robinuav.co.uk/products/d ... amera-lens-excluded

Do you still have any TB50's in stock?

John.

Yes we do!

Awesome, just ordered 2

Thanks

John

Just saw the order, thanks! ;)
Will let you know when it's shipped!

Cheers!

M.

Fab, do you think they'll ship out today?  

Thanks

John.