Looking for turn-key BMS system

Hi
One of my clients is looking for replacing existing HW, 2 200Wh battery modules, which each has a BMS controller, that monitors and balances 12 lithium ion cells (4 series connection of 3 parallel cells). Each of the modules has SOC output in the form of LEDs.
Beyond that, the overall system has a BMS controller that is powered from either 24VDC (grid connected) or from the batteries. This BMS controller also has SOC, with a connected display.
The client would like a turn-key solution, so minimal NRE due to low volume.
I am looking for a supplier of finished batteries with BMS and also BMS controller. Perhaps one of you guys has worked with this? (need a stable supplier)
Client is based in the EU.
Thanks
Klaus