I am planning on making one of these soon. Did you have 2 sets of NIC cubes? I would like to make similar size set.Lovely set up, @Possy . Just a note of caution: those connectors are prone to pop-off, especially with an active rabbit. It's a good idea to reinforce all connections with zip-ties (or in place of the connectors). The added benefit of using zip-ties is that they make a handy door swing as well. (I think I saw a zip tie or two on your cage, but couldn't tell if there are more.)
I'll attach a photo of an old cage of ours that shows the door open to show how the zip ties make a good hinge. A carbiner clip can be used to hold it shut. It's recommended to have a door on a cage so bunny can hop out for exercise without having to be physically lifted out.
You may also want to consider putting a sheet of rolled linoleum on the wood so it can be wiped easily (if you hadn't already planned that). There is lino on the bottom of the cage in my photo. I don't have your well-made wood floor, but you can see how the lino would be a good way to protect your wood. The ramp is optional as rabbits can easily hop up to the upper level.
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