This depends on your daily mileage. Most people charge whilst parked at home overnight . 

A Mode 2 portable charger that plugs into a 3 pin UK socket  will give approximately 90 to 95 miles of range during a 12 hour overnight charge (for example, 7pm to 7am).

If you do less than 90 miles in your daily commute, a 3 pin portable charger is perfectly adequate for your needs.  

If your daily commute/mileage is more than 90 miles then you may want to consider a more powerful 7kW charger (240 miles of range in 12 hours ).

The costs involved in purchasing the 7kW charger are higher at around £1,000+ fully installed.  You will also need a Mode 3 charging cable to connect from your car to the charger unless you purchase a charger with a tethered (attached) charging cable.