we have a number of things in the parish which are the responsibility / ownership of other authorities and utilities - given we are on the ground and looking at these things we need to be able to "case manage" these as well.
we might not own them or maintain them but if there is a loud bang every time a car drives over an "open reach" inspection cover on the road our parishioners will expect us to do something about it.
Local residents do not really care that
the road is County Highways
the verge is Borough
fly tipping is Borough
litter picking is Parish / volunteer
this ditch and culvert is Parish - that one is Borough and the other one is Highways
this finger-post is County rights of way
that finger-post is Parish
This car-park is Borough but the sign is Parish
the war memorial is a Parish asset but is maintained by the "Friends of the Common charity"
The village hall is a charitable trust - Parish not trustee
the sports pavilion is charitable trust - Parish is trustee
Community shop is community interest not for profit
Pub is privately owned
Phone box is BT but they want rid of it but it is kept gong due to poor mobile coverage - possibly could become Parish owned but is in very poor condition.  
telephone exchange building is "open reach?" but the toilet in the building has been overflowing for 2 years.
Cricket Pavilion is on land leased by the Cricket club from the borough but the trees surrounding it is on land leased by the Parish from the Borough.
As the bottom tier local authority Parishioners will think it is the Parish responsibility to "deal" with all the issues locally to some extent and the higher up the layers of authority they will depend on efficient reporting of issues to the "right" place. 
outside a owned asset database one feels a need to be able to add "not owned" assets and accumulate contacts and document interactions overtime