Success! After a couple of attempts and some different options (see right in their colour-coded cases), I have fixed upon the final recipe for Carrot, Apple, Ginger.
This one has a lot of ingredients but is actually really easy to make. You basically have some dry ingredients, some fruit ingredients and some wet ingredients. Mix them separately, then mix 'em together!
So, preheat oven to 180C (160C fan; 350F; Gas Mark 4). Prepare your muffin tin with 12 cupcake/muffin cases.
Then, DRY INGREDIENTS:
150g wholemeal flour (sifted)
30g demerara sugar (or caster or muscavado, or even granulated would do, this isn't a dainty, fussy cake)
25g skimmed milk powder
1.5 tsp baking powder
0.5 tsp cinnamon
0.5 tsp ground ginger
0.25 tsp salt
Mix these together.
125ml vegetable oil
60ml runny honey
60ml maple syrup
0.5 tsp vanilla extract
Whisk these together.
FRUIT - leave this until last so that your apple doesn't brown while you're doing everything else:
75g carrot, peeled and grated (I think a small grate works best)
75g chopped crystalised ginger (small dice)
1 large apple, peeled and grated
(nb this makes for a very gingery cake - if you want less zing and a bit more sweet, you could replace some of the ginger with chopped dried apple)
The easy bit: add the fruit to the dry and mix it about a bit, but don't fuss too much; add the wet to the dry and fold in. Spoon the mix into 12 cupcake cases (about 3/4 full), and bake for 20-25 mins. nb you might want to turn the heat down 5-10 degrees (C) after about 10 minutes, as it's quite a wet mix and if your oven is too hot it will brown on top before cooked through (but the cakes need the heat to start with).
I'm sure this would also make a great loaf cake, although I'm not sure what timings you'd need. If you experiment - let me know!