I read their recent S1 amendment as a potential investor and if made brutal reading.
The Risk factors section states that the auditors doubt whether GH have the funds to trade beyond Dec 2011. I can't imagine too many investors piling their hard earned into a company that has never made a profit based on that statement alone.
Also the departure of Mark Sherman who has been with them throughout rings alarm bells. No nice quotes from him in the press about moving on to a new challenge etc either.