Have you got any reception bars showing? Consider the Virgin wifi app to get free wifi as you move around the city. If the trouble is in a local area have you checked for network issues, use the EE site just google it. Lastly have you changed the network type to 4G or LTE as virgin only use a 3 G service ?
Welcome into the Community and thank you for posting.
Slowness is never the best and I would certainly like to help here. I have been able to test the area and I'm not seeing a great deal of issues. Can I ask whether you're seeing an increase of issues during certain places or time of day?