Derek C wrote:

Just looking at the 'offence' itself, in narrow streets it is often
sensible to park your car partly on the footpath so that it doesn't
block the road too much. I always leave enough room on the footpath
for a pram to to pass.

I hate driving in London, because it is very difficult to find
anywhere to park your car without paying a small fortune to NCP, and
the whole place is covered by confusing local byelaws that you don't
know if you don't live there. In some boroughs you can park partly on
the pavement, but in others you can't.

And I expect that where there are signs to park partly on the pavement, a
car parked completely on the carriageway is prima facie an obstruction.