Preheat the grill to high. Scatter equal amounts of the fine oatmeal and coarse rolled oats onto a baking tray. Top with a sprinkling of light brown sugar to help crisp up the mixture, then place under a hot grill for 3-4 minutes (depending on how hot your grill is), but watch it carefully as it burns easily. Remove when crisp and leave to cool slightly.
Whisk the double cream in a bowl. (I like to do this by hand as I have complete control over it and I beat the cream until it just starts to feel heavy on my whisk; don't over-whisk it.) Add the whisky and honey and gently beat into the cream, adding more of each if you wish, then fold two-thirds of the warm oats through the cream.
To serve, divide half the raspberries between two serving glasses, then top with the cream and the remaining raspberries. Finish with the remaining oats for a crunchy topping and serve immediately.