This was looking like it was going to be a costly pursuit and so I had to try a DIY version first before seeking costly help. I found videoscribe which, of you haven't heard of it, is brilliant. It took me 2-3hrs and £99 one year subscription to create my explainer video which now sits on the website and on YouTube. Check it out and let me know your thoughts
https://youtu.be/c8_ZdmuPhsI