So after watching all those videos (which I have seen in the past) I am still not sure what I did differently. Perhaps I'll try a different pull-though plate design tomorrow and see if it comes out better. I don't use the plastic bottle method because I don't think my batter is fluid enough to do so ( particularly near the end of the pour when it thickens up a bit) and also because it seems like a lot of additional faffing around when i can just do a funnel pour ( the pull-rod comes up through the middle of the funnel, so it seems it would be the same effect anyway - going down into the centre of the mold. Also potentially a lot more soap batter wastage and mess.
@TashaBird should i wait longer before I pull it through? The batter was at medium trace by the time I finished the pour so I didn't want to risk it being too thick to pull through at all. I pulled it slowly, and was surprised at the ease of which it moved TBH. I expected a little more resistance.
How much of each colour do you pour at once? I alternated the colours, with white between each one, several times. Should I pour more of each colour at once or less at once for a better effect?
Any tips appreciated.