Well my original investment wasn't a serious chunk of my...

Well my original investment wasn't a serious chunk of my portfolio, though my current investment certainly is. At that time (2015) i misunderstood the fundamentals of this business as i believe the market did as well. Placing a valuation is obviously tricky and depends on future events and also on the timescale of how long it would take the market to realize this value.  That's further complicated by the fact that for a company that is focused on growth by M&A using it's own shares to purchase other businesses - the extent that the market over/under values the business (in of itself) impacts the value of the business. So the more  under valued the business is by the market the less it's actually worth in intrinsic terms. And vice versa as a self fulfilling prophecy. To say this slightly differently, the longer it remains undervalued in it's history the greater the negative impact on value.

Duration in company's history spent overvalued increases the intrinsic value, while duration in its history spent undervalued decreases value.

Implications on myself personally 

is that when I originally bought before the 2015 SP crash it actually was worth much more in intrinsic terms than it is now due to it being overvalued (if that makes sense). And the crash has severely damaged the company over the near term.

So that leads to what our time horizon is. If your holding time is a couple of years or shorter then the sentiment of the market isn't likely to dramatically change as the reputation of the industry has been damaged for some time to come, both by Slater and Gordon and to a lesser extent by Shine's own actions. Based on what we know regarding fundamentals and past growth, the  fair value presently likely fits somewhere from $1.10 - $1.50. I'm aware that's a big range but this is subject to many factors and valuations SHOULD be vague.

But what if your timeline is way longer than a few years? The actual market/business conditions that Shine operates in are actually very positive for long term outlook (feeding into the above valuation). Memory of Slater and Gordon fiasco and Shine's write-offs will fade -  hopefully the memory of investors will fade faster than the memory of Shine's executives. Eventually we may reach a point where the stock becomes overvalued and perhaps for a protracted period. This will increase the actual intrinsic value - it's not impossible that over a long enough time period it may climb well above my original purchase price.  

Barring unforeseen circumstances based on what we currently know, what is my holding time? Forever.