Don't worry too much about switching. Only customer service, billing and, most importantly, prices change. The pipes, circuits, wires and actual gas and electricity flowing through your home are all the same.
The new supplier performs the switch, and all you do is take a meter reading. Of course, there've been many switching horror stories and sadly, these still happen. But for most, it's a smooth process.
We'll email you every step of the way so you know what's happening. You'll get an email when you've applied for a switch, and an email when that switch has been accepted by the supplier (in a small number of cases, the supplier can reject you).