Line your 9" square tin with parchment paper and leave to the side for now.
Chop up your Twix and shortbread into bitesize pieces, and add to a large bowl with your mini marshmallows and raisins/glace cherries.
In a pan, add your golden syrup and unsalted butter and melt on a medium heat, until your butter has melted.
Take your pan off the heat, and add in your chocolate, and stir together till smooth! If you chocolate doesn't quite melt, put it back on the heat for a few seconds and stir, etc!
Let the mixture cool for a couple of minutes, and then pour into your bowl.
Stir the mixure together, and then pour into the tin.
Add any extra Twix on top, and then leave to set in the fridge until solid!
Notes
This recipe will last for 1 week+ in the fridge, or room temperature if it's not too hot!
You can use all milk chocolate, all dark, or a mixture like I do. I wouldn't recommend white chocolate.
I bought my white chocolate Twix in Tesco, but they're also in B&M!