I took a third at our local show with my Victoria Sponge last year
Had the same panics about the mean ol' judge's comments, which I had seen the previous year - they don't hold back, some of those old biddies - and I was up baking till MIDNIGHT the night before with 5 rejects before I got two evenly risen matching ones. (Yes, I did know I must be mad by this time.) Was not helped by DD2 mistaking a Possible cake for a Failure and breaking it in half to eat it.
Your chances probably depend on how big your show is and how many wonderful bakers in the area, mine might not have taken a third at some more highly respected event, and even at my show there was a woman who took the first in EVERY cake class and probably had since the year dot. Her cakes just did not look like the rest of ours. It may have been Delia, in fact. She even won the Men's Cake Class - err at least, her husband did....
Anyway FWIW I did use the 'whizz all ingredients together at once' method and the cakes didn't seem to be any worse than the old creaming method (in fact I always make cakes that way now).
No cream, as you know.
I used (seedless) raspberry jam.
I did shake caster sugar on the top.
Didn't doily.
I did 5(flour)/4/4 two eggs, dsp of milk, which I think works better than 4/4/4. But you need a few dry runs, to be sure as ovens etc vary.
I'm definitely entering again this year because the joy! the pure, sensual joy! of seeing a little blue card next to my cake was second to none, well second only to the time our cheap, mongrel pony took a third in a showing class.
BTW if the name of your village begins with a W and ends in an E you are going to be a rival! in which case ignore all previous advice, use oodles of baking powder and make sure the cake doesn't get too hot by opening the oven door several times and fanning it rapidly up and down.