We take the indirect route, skirting Lochs Venachar and Achray as the sun sets somewhere unknown among the cloud bomb above us.

It’s dark by the time we reach the Duke’s Pass, catching only glimpses of its heathy beauty as the optional adaptive LEDs squint into each bend. In Sport mode there’s a muted growl as revs are kept usefully high to help punch out of corners, but the apices tighten and body roll escalates, so I ease off in favour of passenger comfort. It’s the first time the car has felt its 1810kg kerb weight. Civilisation is soon re-joined at Stirling, then it’s a hushed and painless 26-mile motorway tab to our overnight stop in Uddingston.

Day two is my Charlie Bucket day, for Uddingston is home to Tunnock’s, the glorious maker of the sweet treats I’ve adored since I was a sugar-charged ankle-biter. In a towering brickwork factory on Old Mill Road, 600 staff are working around the clock to make 13 million Teacakes, Caramel Wafers, Caramel Logs, Snowballs and more every week.

Our guide is Tunnock family member Stuart Loudon – coincidentally an accomplished rally co-driver who has competed in 22 WRC events. We pass huge tanks of chocolate (20 tonnes are made daily), then see boilers turning out molten caramel that’s cooled into thick cables that disappear tantalisingly through the floor.

Arcing conveyors slowly waft freshly baked wafer sheets that are dispatched to assembly stations where each is smothered in caramel before the next layer is hand-placed. The enormous sandwich is then chopped into bars before entering an ‘enrober’, coating them in chocolate.

The whole place is a buzz of machines and stripy-coated workers, with sweet aromas ranging from roasting coconut to baking biscuit swirling all around. Some parts are top-secret – such as the custom-made contraption that de-peaks the blobs of mallow – but we can photograph others.

Many are electronically controlled, but the machine that individually wraps 420 Caramel Wafers in foiled paper each minute works via a blur of gnashing, manually adjustable metal cams. Another sensor-driven station uses robotic carbonfibre arms tipped with super-soft vacuum cups to neatly place each Teacake into a pack of 12. It’s both mesmerising and mouth-watering, and we leave with a generous haul of goodies in tow.