I have made progress on the cab area now, for this stage I needed to use a jigsaw to cut out the necessary holes. The pieces were to small to clamp to use the jigsaw in the ordinary fashion, trying to guide the jigsaw over such small pieces would have been a real pain!
So I made a little table allowing me to fix the jigsaw underneath, drilled a hole allowing the blade to pass through onto a flat surface. This way I would have control of the piece I was cutting, similar to using the bandsaw.