Mods are you best hope of finding out why quoted one speed and you get something completely different. You just have to wait for mods to get back to you
I don't think cab 10 is in operation yet according to https://www1.telecom-tariffs.co.uk/codelook.htm?xid=516856&cabinets=24479 . It is listed as:
Cabinet P10 FTTC being Connected, live due by November 2017 Phase SEP NI 19a Huawei
but w/out a postcode or no. of properties passed nor shown on their map. We know these estimated dates have a habit of not being met.