Just a little observation.
When published in paperback it was in three volumes. The full one that is.
That first volume is really easy to find second hand. Used (some time ago to be sure) to clog up second hand and tat bookshops.
The second volume was harder to find, quite rare in fact.
The third volume, not sure I’ve even seen it on Amazon.
I assume that sales rather dropped off for the later volumes….