If you are concerned about the risk of salmonella, pasteurise your eggs first.
Using an electric hand mixer, whisk the eggs for 2 minutes, until light at fluffy.
Slowly sprinkle in the sugar, and continue whisking until dissolved.
Pour in the cream, the milk, and finally add the vanilla extract.
Continue to whisk until everything is evenly incorporated.
Transfer the mixture to an ice-cream maker, and churn for about 30 minutes, until almost firm.
Meanwhile, bash or blitz the potato crisps to a fine crumb. Add just enough of the caramel sauce to create a mouldable mass, then roll into small balls about the size of a chickpea.
Arrange the balls in one level in a suitable container, then transfer to the freezer for 5 minutes.
In the meantime, melt the milk chocolate in the microwave.
One by one, submerge the crisp balls into the melted chocolate, and remove with a fork to place on a lined baking sheet.
Place the baking sheet in the fridge, or freezer, to allow the chocolate to firm up completely.
Scoop the ice cream mixture into a freezer safe container and ripple through the remaining caramel sauce, along with the chocolate and crisp balls. Freeze until completely solid - at least 4 hours.
Notes
If you don't have an ice cream maker, freeze the ice cream mixture completely and then whisk up with an electric hand mixer to break up all the ice crystals.You can then add the caramel sauce and crisp clusters, and then refreeze everything.