Moving over to the gutter gives you so many problems. They are the same problems as with a bicycle, but you are going much faster. These are why you sometimes see cyclists further out in the road than you might expect.
First, the gutter is where all the crap gathers - glass, gravel, water, potholes, slippery white or yellow lines, nuts and screws etc. They can all be hidden and are environmental issues that will affect your bike's handling - if you have to swerve, neither direction is safe for you if you are being overtaken. Force others to overtake you safely and give you some distance.
Second, there are pedestrians to worry about, who often step into the road to go around other pedestrians, and it is surprising how few look before they do it. You need to make sure they would not affect you if they do it.
Third, following drivers will assume you have pulled left to let them through (as you wrote) and they will overtake when it is very unsafe to do so because of their impatience and much too close - often leaving you with no room for error and often making three vehicles abreast. This leaves you in a very dangerous situation. Worse still, if the overtaking vehicle is a bus or a lorry, the backdraft from their vehicle will put you off-balance if they are too close, and can pull you under while they are alongside, or can impact on you just after they have gone past - being so close to the kerb, you are a candidate for a serious accident. What happens if they are overtaking and you spot you are about to hit a great big pothole, or water, or pedestrian? You are the one that will be dead.
Fourth, the gutter is the precise reason for SMIDSY's. To traffic wanting to pull out as you approach them, you could be hidden by a tree, by a lamp-post, by pedestrians, or by the metal edge of their windscreen. You need to be central to your lane in these circumstances to maximise chances of being visibie.
How should you do it? You should never sacrifice position for safety. If you are in the middle of the lane, or just left of middle, you are much more visible and following traffic has no option but to take you into account and wait behind until it is safe to go. Let them get in a bad mood, screw them - NEVER COMPROMISE YOUR SAFEST POSITION, even if other bikers try to tell you to move over. If you feel you are holding up traffic too much, do what tractors do - pull over in a safe place (spot your stopping place, indicate first and slow down gradually) and allow the traffic queue to pass and then rejoin safely.
And definitely wear reflective and hi-viz gear at night and in bad light, alongside a good helmet, gloves and boots. If you can afford it, get armoured gear for your elbows, back, shoulder, knees and hips too.
