@BlingLoving the banana crumble turned out very well - at least there isn't any of it left.
I did tweak the recipe, so it was more in line with other banana puddings/fruit crumbles I've made in the past.
The ingredients I used were:
Fruit layer
8 peeled, sliced bananas (defrosted),
3 oz soft brown sugar,
1 oz butter
Topping
3 1/2 oz/100g plain flour,
2 1/2 oz/75g butter,
2 oz/50g rolled oats,
3 1/2 oz/100g demerara sugar.
Sauté the bananas in the butter and soft brown sugar until they form a mush. Pour into a greased baking dish. Make the crumble topping by rubbing the butter into the flour until it resembles breadcrumbs. Then stir in the oats and demerara sugar, and spoon the mixture over the layer of bananas. Bake at 200 C for 30 - 40 minutes until hot and bubbling.
I've now slightly altered the crumble topping recipe by replacing some of the flour with polenta (trying to eke out the flour). But no one's tasted this one yet so I've no idea whether it's successful or not.