I bought myself a tanglewood TW28 st-e off of ebay about 2 years ago for £75. It's in pristine condition and the time has come to sell it. It is an electro-acoustic but i cant find any record of these ever being produced. It has an artec pickup which is powered by a 9v battery. It did cross my mind that it may have been a retrofit but i doubt the fitter would have gone to the effort of adding an "E" to the model number printed in the sound hole of the guitar. Any ideas?