Is it reasonable to leave a family dining table behind when it won't fit our new flat?

Dad asked whether we'd use the family table for our first Christmas in the new flat. I said yes before measuring the dining area. Now I have the measurements, and there isn't room for the table and chairs in a usable arrangement.

The table belonged to my grandparents. Dad is downsizing too, so it cannot stay at his house. Our new place costs less than our current rental, but the dining area is much smaller. We could keep the table in storage for $65 a month, or ask another relative whether they could genuinely use it. Nobody has offered yet.

My partner thinks paying to store a table we can't use would undermine part of the reason for moving. I keep picturing Dad asking where it is when he visits. I know this started with my own premature promise.

How do I explain the change without treating the table as unwanted clutter? I want a smaller home that works, and I also want to handle an object Dad entrusted to us with some care.