What have you done today with your Austin Seven

[Dave Mann]

I knew if I looked I'd find the answer, here are two contractors comments: "If automobile traffic is your main consideration, bollard spacing should be no more than five feet apart. Even the smallest automobiles available will be prevented from entering at this spacing. If fork lift or other industrial vehicles are the vehicles to be denied access, consider the width of the thinnest vehicle to be stopped and ensure that your bollard spacing is tighter than that vehicles’ width.
They can be installed close to the curb if there is no vehicle parking allowed. they can be installed close to the curb. The distance between bollards should be between 3 and 5 feet, enough to allow for pedestrian traffic and wheelchair access, but close enough to deter the entrance of a vehicle."
Whilst the DOT is a bit more precise: "D.O.T. CPNI (Centre for the Protection of National Infrastructure)
Traffic Advisory Leaflet 02/13 May 2013 (as amended October 2017)
Bollards and Pedestrian Movement
To meet security requirements, bollards must be positioned to maximise blast stand-off distance, and spaced at a maximum air gap (between bollards) of 1,200mm. Additional considerations include meeting objectives for health and safety, site operation, cost and aesthetics. 47,24”
I don'y know what they mean by blast stand off, obviously if they follow the DOT specification they will use more bollards putting the price up so 5' appears to the general gap and they haven't heard of Austin Sevens.