Mobile data speeds can sometimes vary, this is indicative of varying amounts of traffic on the network at the time - are these speed tests during the day or other times?
As a first-line check, I'd recommend looking at the coverage & status checker , and using the "check network" (not "check network") link to filter for any known issues in your area. You can also use the "report a problem" link on there to enter the details of any issue not yet showing, and pass it to EE network teams.
Do you have an EE mobile - and if so, what are data speeds like on that?
