After some good watering advice from @Herbalize, there has been some improvements with my leafs which are now growing out much further! I've also added some occasional light wind through a fan which has helped it's sturdiness!
My next step is to think about what soil to use when I replace the current soil (as it runs out of valuable nutrients soon). Are there any tips or videos I should be watching with 'soil changes'? I'm thinking about going for the vitalink professional soil, however I'm also a little confused about whether or not I should use additional nutrients too to this? I'm currently using 'no addtional nutrients' - is this correct?