Hi Theo,
Personnally i wouldnt worry to much about the 15 sec opening sting – brides wont be interested in that, spend your time on your showereel, create 4 highlight montages from the weddings you have done… this really should be your own work, unless you plan to out sorce all your editing in the future, cleints will want to see your work to give them an idea of your creative skill and the quality you produce.
Im no expert, but you can look at the clips on my site https://www.razzelcam.co.uk, i normally get around 4-6 bookings from each wedding fayre i attend here in the UK.
Regards
Martin