Dear MikeWales007,
Reading your recent posting it would look like by reducing your weight you have found out that you need less insulin to still acheive relatively good B/G control. I certainly would think it wasn't a good idea to suddenly cut out using insulin in one move but continue as you are in gradually reducing the level, whilst still monitoring your B/G on a regular basis. By doing it this way, it will mean that your Beta cells will then become slowly accustomed to releasing and producing insulin, for after all, as you say you have been using insulin for these last 5 years, so your body will naturally take it's own time to re-adjust.
If you should decide to wean yourself off insulin do so with your Dr or Dn support, and I imagine that you know all about GL loadings, so please be aware of avoiding those nasty GL's that can spike your B/G levels and place undue stress on these delicate recovering beta cells.
Please let us know how you get on