Interesting Steve, the modern way of doing things now there's this high awareness of 'adopted' highways and the councils lack of wanting to take responsibility of anything more than they have to leads to these 'private' areas. We've got quite a few in Plymouth in new build sites, and invariably, the lighting in the private carparks is always at complete odds to what is installed on the adopted highway. Some examples include:
(Highway Saph 2 60w Cosmo, Private P567 70w SON)
(Highway Saph 2 60w Cosmo, Private Tamlite Tamglobe 70w SONE)
(Highway Saph 2 45w Cosmo, Private Tamlite Tamgrove 70w SONE)
There are sometimes exceptions to the rule however, as we have installed some lighting for developers on non-adoptable sites using council spec equipment. Dare say it costs more but should last longer anyway