"Hello Simon. For the length of time you've been playing your swing looks really good. What you need to focus a little more on is trying to source less power from your shoulders and get more from 'leverage' by swinging your arms, wrists and club more efficiently.
"Most beginners try to force it with their shoulders, but pros are able to get massive clubhead speed from 'swishing' or releasing the club at the right moment.
"One drill I would like you to try is the 'L' to 'L' drill. Try with a 7-iron and the ball teed up and your feet positioned nearly touching. From here your focus is a 3/4 length backswing forming an 'L' shape between the shaft and left arm, then without pulling with your left shoulder, but more focusing on the clubhead, whip it through to another 'L' shape in the finish.
"Work this feeling, then gradually widen your stance. Your aim is not to 'yank' the shoulders through, but 'swing' the clubhead with free wrists and more leverage. Good luck, if you get it right you will be suprised how far you hit it like this."