How would you fix this.
Address is on a busy primary street without street parking.
Parking lot is at the back on a different road off the primary street address?
I have my own thoughts but it seems inflammatory. 
Would this be a case for forcing a house number?
Open to suggestions.
Yes. But also need to make sure google has correct location for pin for both the address and the business, and put in parking lot segments per guidelines in the wiki.
“The Waze development team is working on a way to specify a stop point on a street other than the named segment to which the address is attached. This is important for any house whose driveway may not be on named street, mall location, unnamed long private streets/drives with multiple addresses, or businesses which have an entrance from a parking lot off the named street. At this time, there is no way to guide the drivers within a parking lot”.
Thanks.
BTW I had a chance to change an address in the Google Map by picking up the pin. Could be tricky
if the road segment is split or in the other side of town.
Regards
That note from the wiki which I wrote, is specific to House Numbers within the Waze editor, which aren’t active in navigation search except in rare circumstances. When any other provider returns the destination location, Waze navigates as close as it can to that GPS location, regardless of street type, etc. Functionality of the Waze address stop point in testing actually reduces the functionality of the app routing because it will stop navigating at the named street instead of the actual address location.