Immigration Law Professional

I am in New Zealand, I originally came to hike with friends however I really didnt enjoy that, so I decided to apply for a work visa instead. In the UK, I am currently under investigation for a charge of Harassment without violence which I deny and I have a trial on 2nd April and a plane ticket booked for 23rd March to return to the UK. The trial was originally on 28th October but due to procedural errors by the prosecution it had to be adjourned and I had already booked my tickets to come out here. Because of this, INZ have indicated I will require a character waiver. I have previous convictions but nothing in the last 5 years and no similar offences. In the grand scheme of things it's a relatively minor charge, and I don't feel that i would get declined a visa if i had plead guilty or was found guilty. So i am not sure what the problem is really. But i am looking to get an idea of how much it would cost if i was going to hire someone to help me complete the form. I have a police certificate which I have submitted already.