They just tell me to upload it every week, but I don’t see what the point is because if they’re not going to see it or purposely look at it then why?
I don’t always email them now as I started having anxiety attacks when I did due to their treatment of me most of the time and making me feel like a problem/burden.
It may be that the data will be lost/overwritten on the device if you don't upload it reasonably often, if this is what happens and you do only do an upload just before your appointment they will only have the last week+ (or however much it can store) available to evaluate.
While they won't peruse all that much of your data, they will look at the trend graphs and I would expect them to be interested in the same period of time that is covered by your HbA1c test (i.e. 3 months).
They will know if an upload has occurred if they happen to look at your data, I doubt they will chase you though unless it is during your appointment.
I'd have a look at how much data your device can store, and upload it before it's completely full to ensure there's a complete record.
fwiw I use XDrip+ and it automatically uploads to Tidepool, which is linked to MyDiabetes. My consultant uses Tidepool, the doctors' surgery use MyDiabetes (though I don't think they actually look at it, which is fine.)