Just a quick query - not been able to find the answer anywhere else - The final tick of Lifebloom is logged as "Targets Lifebloom heals Target for X" does this mean the Bloom causes aggro for the healee not the healer?

Yes.

mmm, I think it was changed some time ago where the person being healed by the bloom would no longer get aggro because of it. At least that's what I had read on various forum posts. I've never taken the time to properly test it out...

The final tick (like PoM) counts as the target healing themselves, I've seen no evidence that you will get the threat from it, or any change that means the target gets no threat from it either.