Having spent over a year trying to solve exactly the same puzzle I can tell you that 'Kevi' no longer works for the city farm and has proved to be 'uncontactable' so far.
Those at the farm will try to help where they can but they are not a grave finding service,they are a farm ! Bear in mind also they are a community project that is under threat from ever decreasing funding and a minimum of staff !
It appears that virtually ALL the records were destroyed during the WW2 bombing 'blitz' of the liverpool docks and seafront and St Nicholas Church was hit and burned very badly.
The example shown is from a ledger held at Liverpool Records Office in the main Library and is one of two that were salvaged from a 'skip' allegedly, therefore are not a complete record of the cemetery layout.
More here -
http://forum.liverpool-genealogy.org.uk/viewtopic.php?f=2&t=12883 The prospect of locating ANY common grave interments I have to say, is nigh on impossible without the
exact field reference,row location and compass reference.
It should be borne in mind that many tens of thousands of people from the workhouses,the prison and other such institutions nearby were buried as many as six deep in the 'common' plots !
1916 - 1919 during the Spanish Flu pandemic would appear to have been a very busy period for them.
Like so many others,myself included, we just have to settle with the knowledge of the sites existence and little else as yet,unfortunately.
Life had treated them so unkindly and continues to do so even in death.