Concentric,
Yes - I hadn't considered that the "second type" might have originated in the 225 (then possibly been distributed in L2s as units get swapped for overhaul). I guess the casual treatment of the rejected gears during 2001-9 may come down to not expecting them to fail suddenly, or regarding spalling as normal wear and tear.
The AAIB report, whilst thorough, didn't conclude why these gears suffer fatigue in the way they do. This led to some fairly woolly recommendations about assessments of continued airworthiness etc. It appears to me as if AH have then stood by their design and put extra monitoring requirements in place rather than doing much research into the component suitability.