Use normal cloth tape, 3M or similar, much better than PVC/insulating tape in 99% of the cases.
The way these vehicles were put together, wiring wise, is appalling.
If you feel unable to find these clips anywhere, try to find part no. EYC10008L "clip-trim retention", should be common to other LR models. Still ...go to a breaker I am sure for a couple smokes, coffee or a beer, you will leave with a handfull or two.
Usually they go out with the trim piece, but often remain in the hole in the body, directly with the (now broken) plastic trim tab. Small, long-nose pliers or two small scredrivers working in unison are needed to take them out. Work one side only, the plop out easily - sometimes they fly out as well lol.