Fingers crossed you hear soon

.
Officially you are not allowed to upgrade to priority after the application has been mailed - and so it's a gamble as to whether they will honour it. Someone tried to upgrade several weeks ago and they've only just got their visa.
Even if you tried it, I'm not sure it would be any quicker than just waiting... since you're already at 10 weeks anyway. Unfortunately, your solicitor gave you bad advice about priority processing - it usually shaves several weeks off the processing time, especially at this time of year.
If you purchased the shipping labels from the VFS Global website, it will be UPS 2-day shipping.
UKVI no longer accept shipping labels from FedEx and will not return any packages using them.
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