Filtering issues when used with a form

I am trying to create a form that pulls out the lines of information relating to the data that is put into it from the combobox list.

It is working fine when the fields match with something in the list; however, when I want to show all and run the report it keeps filtering everything out rather than leave everything in.

I have set the variables up as public and they match the data in the spreadsheet.

when the variable = "All" I have put in the following code

if Locality = "All" then
ActiveSheet.Range("$A$4:$UO$475").AutoFilter field:=FieldNum
end if

When the line of code is done in isolation or recorded as a macro it makes the autofilter show all but when run as part of the code it unselects everything.

It seems to be having issue with the "All" as it is not on the list of possible choices in the spreadsheet but is an option for the combobox.

Please help me!

I just need a default setting that will allow thye report to run with all data showing if "all" is selected.

Also bear in mind that there are 2 comboboxes and each can be either selected as specific variables or as "All" or a combination of both relating to 2 different fileds.

Thanks