Although I understand how frustrating you find this situation, I have to mention that all STOP junctions have a STOP sign at the junction. The Stop sign (regardless of the paint degradation) is ultimately compulsory! Stop signs are place at junctions where visibility onto the new road is obstructed or where traffic is heavy. Effectively, they are there to help make a dangerous junction safe,r for both you and other road users. On arriving at any form of stop sign or signal, you must bring your vehicle to a complete stop, apply the parking brake as you look right, left and right again. You can exit the junction only if it is safe and correct to do so, without causing another road user to change speed or direction. I have to say the CPS are being as lenient to you as they can possibly be, dropping the charge from dangerous driving to due care and attention is pretty good going. Finding a way out of the charge altogether in being unrealistic as you did cause an accident. Be grateful that you did not cause death or serious injury to the occupants of the other vehicle as you so easily could have done. Put your hands up scorge and let that be and end to it. I wouldn't mind a side bet that the local council will have re-painted the stop line.