Hey, Sorry to hear your both having the same problem. I been having the same problem but after doing some research I came across some info. Apparently the speed control sensor found at the bottom of the gear box is faulty. It's a common fault. My cuz also had the same problem and he changed the control sensor and it seemed to have worked. The sensor doesn't cost much either. Something like £20-30. I still need to get mine done but thought i'd share what i know with y'all.
Yes, it is the speed control sensor, £26 inc vat from ford. When it stops working the senor tell the engine management you are not moving, although you are, and it reduces your power, so you end up a bit sluggish, For replacement leave it to your garage, as the car needs to be up in the air, its located at the back of the gearbox. Its a swine to remove as there is a pin that doesnt want to come out...deffo not a roadside repair. My local garage charged me £10 to replace it.