RAFU.
I disagree with Penny and Widget, 2500 polys for a model is HUGE!

A5 can't really handle it... it wasn't made to. The "hole" you see are affected by the clip range.
Because their are a lot fo polys in the model, some will disappear. With a5 you can howevert adjust the clip range. BUT I suggest that the model you are using has too many polygons. Still look up clip range, and change the number higher than the default in your wdl.