The initial injection was I believe £1.25M This increased to approx £1.5M but additional losses have accumulated over the last year.
They are looking to recover the cash injections to date this plus a premium, hence why none of the interested parties have come forward with an acceptable offer.
We'll have to take your figures with a pinch of salt but if we did take them on face value. If you had £1.5 million + and were interested in the club would you hand that over to cover what could be sunk (unrecoverable) costs from Bower's running of the club? Unlikely. You'd wait until the club was next up for sale at a fair price.
Clubs are well known money pits, the way you increase their value is via infrastructure, significant fan-base growth and ultimately success on the pitch and access to improved TV payments. The current owners as yet have done little on these fronts.
The club has minimal infrastructure, potentially accumulated losses that you point out and an East Stand to finish etc etc. We all laughed at Giovanni De Stefano who offered a pound, Cardoza said in court he traded it to the Bower consortium for a quid. There's a pattern forming.