Tree preservation zone

There is a problem

1000 entries with tree-preservation-order field must match the reference field in the tree preservation order dataset

reference: ZZZZZTESRW168
name: South Bucks District Council (No.8) Tree Preservation Order 1991; dated 4/6/91; made under Sections
tree-preservation-order: undefined
TPO/SBDC/1991/08
tree-preservation-zone-type
geometry: MULTIPOLYGON (((-0.648390 51.607831,-0.648436 51.607842,-0.648480 51.607845,-0.648524 51.607840,-0.648551 51.607834,-0.648574 51.607825,-0.648588 51.607818,-0.648614 51.607801,-0.648627 51.607787,-0.648639 51.607769,-0.648645 51.607753,-0.648646 51.607743,-0.648645 51.607723,-0.648641 51.607712,-0.648631 51.607694,-0.648624 51.607686,-0.648607 51.607670,-0.648597 51.607663,-0.648576 51.607652,-0.648545 51.607641,-0.648529 51.607637,-0.648499 51.607632,-0.648470 51.607631,-0.648442 51.607633,-0.648403 51.607641,-0.648378 51.607650,-0.648348 51.607666,-0.648331 51.607680,-0.648320 51.607692,-0.648306 51.607719,-0.648304 51.607728,-0.648304 51.607745,-0.648305 51.607754,-0.648312 51.607772,-0.648329 51.607794,-0.648340 51.607804,-0.648356 51.607815,-0.648390 51.607831)))
point: POINT (-0.648475 51.607738)
notes
entry-date: 2017-07-04
start-date: 2017-07-04
end-date

Your data is missing a tree-preservation-order.

The Tree preservation zone guidance explains how to fix the issue:

The reference for the tree preservation order that covers this zone.