Verdict: ReBoot cake

Oddly enough, it was actually rather good! I had been expecting a monstrosity, but it turned out very well - moist and delicate. Sweetness was perfectly balanced and the various competing flavours complemented each other nicely. The beetroot was barely noticeable, but there was just the slightest hint of it in the background (though I suspect this may have been partly because the beetroot didn't seem overly ripe). It wasn't quite perfect - the lower half of the cake was a bit too moist and slightly soggy. It really could have done with a bit longer in the oven, but the top was getting dangerously dark so I decided to take it out rather than risk burning the top. All in all, rather successful, I'd say!
If anyone's wondering how to transport a cake without a car, this is how!