such things are set by the certification rules. Manufacturers have to demonstrate emergency evacuation with the specified seating configuration.
Do the Emergency Exit Specifications include allowance for the use of bulky Survival Suits and Flotation gear over heavy Winter Clothing?
All the passengers are not 165 pound "average" folk especially when outfitted for a Winter time flight over the North Sea.
Pitts gets a Gold Star on this one.....as I have in the past noted the very small percentage Helicopter Costs are in an Oil Company's Transportation Budget. Don't tell me they cannot spend a few Bob extra to enhance safety and comfort for their employees who fly out to Sea to get to work.
I can assure you their CEO's Gulfstream V has spacious seating.....and damn fine catering to boot.