Hi rawiri,
I've found a probate record (will) for a Eric Herbert MEADOWCROFT filed 1972 held by Archives NZ Auckland. Is that him?
I agree with Zephyr, the easiest way is to get recollections of your family by interviewing the oldest surviving generation, or in my own case, old family friends. Friends, especially women, remember a great deal about those they were close to, and here's a tip: they can often pin down dates for you by recalling the birth of their own or their friends' children, or linking them to other major events in their lives. Write down their stories because although they will often distrust their own memory, from my experience they were not often wrong.
Failing that, look for written family records that might give some clues. You'll soon start to build up a picture of those you're looking for, occupation, where they lived and possibly died, marriages, etc.
If you suspect you know where these individuals lived, check out the local library; they may appear in local history books, electoral rolls, rates books, card indexes, obituaries, newapapers in social events, etc.
Can you tell us anything else? Full names, where they might have lived? By the way, is it TUBB or TUBBS?
riley