induction hub in front of toughened glass - would that be OK for fire regs?

There isn’t a UK Building Regulation that specifically prohibits installing an induction hob in front of a window. Unlike a gas hob, an induction hob has no naked flame, so many of the concerns around draughts extinguishing burners don’t apply. The Building Regulations focus more on electrical safety, ventilation, fire safety and following the appliance manufacturer’s installation instructions, rather than banning this layout outright. In your case, with an aluminium-framed, toughened glass window, no internal blinds or curtains, and the window around 150mm above the worktop, there’s nothing you’ve described that would automatically make the installation non-compliant. However, the hob manufacturer’s minimum clearances to combustible and non-combustible surfaces must always be followed, as these can vary between brands and models. It’s also worth considering how you’ll provide effective extraction, as steam and grease can quickly mark the glass. I would recommend a downdraft induction hob. If you purchased a BORA hob, it would extract 98% of grease and cooking smells if vented and around 87% of grease and cooking smells if recirculating. If you’re planning a new kitchen, it’s definitely worth discussing the layout with an experienced kitchen installer. They’ll be able to check the appliance installation requirements, ventilation, electrical provision and practicality of the design before work starts. Every kitchen is a little different, so having the design reviewed before ordering units is always worthwhile.