Thanks a lot for getting back to me @mcaddy and I'm glad to hear that upload speeds have increased on your end too.
So the GEA results, and availability on the line aren't related, for instance, you can have an excellent service, but maximum speeds on the line can still be 40Mbps depending on it's distance from the exchange.
I've checked the availability status for your line though and can confirm that it could achieve speeds of up to 80Mbps, and upload speeds of up to 20Mbps, so the option to upgrade to Unlimited Fibre Extra would be available.