Just edited my post with circuit boards on adding their names.
A breaker has agree to let me try a replacement head before buying. However its a very expensive fix. If the replacement solves my problems i still would not know wether its because the head unit is damaged or i've messed up the coding. So i'd probably be best getting the coding done first or is my logic wrong?
When you make coding changes, are the changes stored in the cars memory or in the memory of the parts the coding is changing.