Hi Andrew and thanks to everyone who has responded so far.
Laminated the panel ?

I think I skipped that and went straight to drawing on the board.
It worked! I was successful at carving a little kitty into a piece of poplar wood in bas relief. It wasn't the end-all be-all of carving - some of the deep parts are rather rough, I'm not sure what kind of tool to use to smooth in areas where you can't get sandpaper, and more of the design was flush with the original surface that really should have been, but it didn't turn out too bad.

I figured out what I was doing wrong, why the poplar was splintering - it's just that I wasn't making the cut with my razor-pen deep enough, and also when I was using the chisel to remove a section 'into' the razor cut I was hitting it a bit too hard. The part in the following text about 'trenches' is excellent, that worked great, and also the part about 'curl of wood' is appropriate, this text pretty much sums up what works LOL. Again - it worked, and poplar was the wood I used on my first attempt.