Re: Whirlpool 2000Plus ceramic hob.
As far as i’m aware there is no requirement to provide any ventilation, or indeed any way of creating any either. The only thing you could do is check that the opening in the worktop is as stated on the fitting instructions which will probably give 5-8mm clearance around the body of the hob to prevent some direct heat transfer to the worktop.
If the customer insists that it’s getting too hot then perhaps refer her back to Whirlpool?
I was once informed by a manufacturer that the edge of their hobs could reach as high as 80c and that this was within within the regulations 😯 …how true that is i have no way of knowing though 😕