Either that is one of the first ones ever made or it almost appears to have been rewrapped with heat shrink...... ?
You might try looking at putting in a wanted add in RCgroups to see if you can find one. Supposedly they have a new buyer
in the wings to keep things going. The Wren 44 TP I have has the older ECU and when I need service ; subject to them reopening;
one of the first things I will do is upgrade to the new Xicoy V10 ECU as those should be available for a long time to go as the older ESC's will gradually dry up.
http://www.turbinesolutions.co.uk/
these they guys ; apparently they are doing Wren repairs.