During a Motorcycle meet at Box Hill in Surrey ( South West of London ) about 20+ years ago , saw an Enclosed Sidecar with seating for four children !
Parents were on a Triumph Motorbike and the Sidecar - which was almost like a miniature Caravan - was mounted on left hand side . Door on outside & the kids - aged about 3 to 7 - sat on two seats at either end , facing the middle .
It was so large you could hardly see the Bike from that left angle !
Think it was a custom job made mainly from wood ? Nearest I could find was model for two adults one online & those are much taller . See 2nd & 3rd photos down :
http://www.steves-workshop.co.uk/veh...ecartypes.html
And probably slightly bigger but not as wide as this one :
http://www.hannigantrikes.com/produc...ro-22-sidecar/
And this Motorcycle Ambulance is just so cool :
https://www.thenewsminute.com/articl...mbulance-63149
Even in the late 1950's when very few families had Cars in the UK , my Mother's Partner recalls four or five member families being piled onto standard Motorcycle-Sidecar combinations . No 'Health & Safety' then ... 8-|