Quick model request

I have been trying and failing for far longer than my patience will last to do what I imagined would be a simple task - chopping a model into two pieces. For one reason or another I’ve been totally unable to get it to work, so I’m going to put it forward to anybody with a spare few minutes. What I need is basically just to have this model chopped into two, as it has too many vertices for Hammer to handle with one model. It doesn’t need to be compiled or anything, I can manage that myself (probably), I just need the model to be split into two SMDs. I apologise for having such a stupid request but I cannot get my head around any of the modelling programs I have tried and I do not have the time or patience to fuck about any longer.