Check the lables on your smoke generator. UK power operates at 50 hertz. US power at 60 hertz. If you have a 60 hertz smoke generator, you will need a converter to make smoke generator run on UK power.
Smoke should not be coming out of the bisquette feed tube. Smoking backing up into your smoke generator will, over time, damage the smoke generator.
I suspect that you don't have enough air moving through your smoker cabinet. Your cabinet should hold the smoke temporarily, so it needs exhaust and inlet vents. I found a calculator for sizing smoker vents on the internet and it indicates that the volume of your vent (exhaust opening and chimney height) should be 1.7% of your cooking chamber volume. Not sure this is absolutely accurate, but it should be a good starting point. Your air inlet area, including the hole for the smoke generator, should match the volume of your exhaust vent.