I may have missed the boat on this one, me being new to the site but a Shawarma, or Doner Kebab has been widely copied on other food web sites, including the Glebe Kitchen video on you tube,
Profoodhomemade with another YouTube link
https://profoodhomemade.com/doner-kebab-meat/
And for those who like a garlic sauce with their kebab, I found this small batch Lebanese Garlic Sauce (Toum) at this site
http://chichoskitchen.blogspot.com/2010/04/toum-garlic-lebanese-sauce-recipe.html
I cannot claim any authenticity and have never tried these versions myself, but they have had a decent write up elsewhere.