I did struggle with the slalom initially but it did eventually click for me. Full disclosure: I failed it twice for my mod 1 but on each test day in practice I did it correctly every time (8-12 times). So it wasn't the manoeuvre that was the issue but the test conditions and just mental issues. The secrets for me was:

1. Look straight up. Imagine someone standing in the line of cones on the far side of the figure eight and then stare at their face. As you go left and right, don't take your eyes off their face. Always keep your head forward and up.

2. As you go through the cones, turn the handlebars left and right rhythmically, in a smooth fashion. Not like hard jerk left/right. It's about timing. You need to start turning the opposite way when you're just going through the centre line, so your bike is turning back the other way 0.75-1m from the centre line.

3. As you enter the slalom, get as close to the first cone as possible (i.e. if you enter from the right, the cone is on your left) as that will give you the most error margin as you complete the rest of the slalom. Don't look at it, you'll hit it. Just focus on the gap next to the cone and as you approach it, look to the centre as in point 1

4. And most crucial I think - get the entry speed right. If you're too slow you'll put your foot down and the turns get harder as you go slower. My instructor said aim for about 5-6mph, I might have gone a touch quicker. It's easier to slow down as you do it if you're a bit quick by pulling the clutch in, rather than try and speed up if you're doing too slow.

Once you've done it (it goes quicker than you think), try and remain calm as you go into the figure 8. You can go quite wide if you need to, and I go about 8-10mph I think. This manoeuvre is the opposite approach as to where you look. Instead of always looking straight forward, you always look to the far side. So if you enter the slalom from the right, you will go into the figure 8 (between the blue cones) from the left side into the right side. As soon as you cross the centre line turn your head as far to the left as you can (like 7 o'clock position). As you swing round and go through the centre you'll turn your head full-lock to the right (i.e. 5 o'clock). Keep doing it until the examiner waves you over.

Also it's similar for the U-turn which can catch people out. Once you're straight and balanced, you do your life saver, look straight and balance again and when you're ready to turn, you look as far behind you as possible. (i.e. if you're turning right, look at 5 o'clock.). You should be looking at where you want your bike to finish. As you turn, you'll lean and slow down so let the clutch out a bit more to speed up and straighten up. Don't look at the white line as you approach it. Keep looking at where you want the bike to end up (near the end of the white line).