You appear to be under the belief that your speed will be 100% guaranteed via WiFi, this is definitely not the case. You can occasionally get the full speed however the only way to really "consistently" get the full speed, or close to, would be using a third paty router or WiFi mesh system. Speeds that you are sold are directly only to your Hub and "can be impacted by things like your use of WiFi, your equipment, internal wiring, peak time congestion and the number of people accessing a particular website." - The quote is a direct line from the Broadband Speedcode that is read at point of sale alongside the email sent out ~7 days after taking said package. Your minimum is 54Mb to the Hub itself, if there are any doubts you can connect up a Cat5E or Cat6E/7 cable to a laptop/desktop with a capable 1Gbp/s ethernet connection, you can find that out by simply Googling one of two things; "Check speed of ethernet adapter" or by typing in the device name into Google and finding the specifications; an example would be "Acer Aspire 5 Slim Laptop specs" we can find from Acers Website and places like Amazon etc that it has a Gigabit Ethernet Port which means it can exceed speeds up to 940Mbp/s. Area faults can play a factor in poor speeds too.

** I work for VirginMedia but all opinions posted here are my own.