Number Data Field Won't SUM

Hello All,

I'm trying to create a very simple visualisation showing the total of my team's proposed budget spend per country. I only have three columns in the Sharepoint list I'm importing from; Date, Country, and, Proposed budget. There is a date field a text field and the proposed budget field is set up as a number field on the Sharepoint list (I know Power BI won't sum non-number fields). 

When the data is imported into Power BI Desktop the only amalgamation options I have for the proposed budget value are 'count' and 'count distinct'. There is no option to sum. I have checked, rechecked and re-created the Sharepoint List that feeds the visualisation numerous times ensuring the proposed budget field is set to 'number' yet Power BI seems to keep interpreting it as a text field and therefore does not give me the sum option.

Am I missing something here or is this a design flaw with Power BI when importing data from Sharepoint Lists (i.e that it considers all columns to be text no matter how they were classified in Sharepoint)?

Any help would be much appreciated.