I am trying to display a graduated symbology for a vector layer based on UK postcodes, but having major issues.
I have the postcode vector layer, and my data set is UK Postcode Lending data, where I've taken only the last column of data (Q2 2019) and saved this (along with the postcode sector as column 1) as a csv and uploaded to QGIS 3.12.3 Bucaresti. I'm running a Macbook Pro 2016, Mac OS Catalina 10.15.5. So far so good.
I've then joined my attribute only table of postcode lending data with the vector layer of UK postcodes, using postcode sector as the join. The join goes through, but the lending data gets saved as a Qstring text layer, not as an integer, no matter what I do. This is where the problem starts, as QGIS obviously can't make graduated symbology from a text attribute type.
I've tried to run Refactor Fields from the processing toolbox, but this doesn't change the attribute type for some reason, even though that's what it's supposed to do.
I've also tried reformatting and importing the CSV file so that QGIS imports it as an integer type off the bat - again, no dice.
These are the only two solutions I can find on the message boards, and I don't know why it's not working.