Just labelled yesterday's product, and yes, it did include fruit from our little orange, lemon, and lime trees.
The best oranges for #marmalade, perhaps the only ones, are Seville oranges, as I'm sure you know. The Sevilles are very seasonal, and Tesco had none the last few times I looked, but I found a source.
https://www.parrishfarms.co.uk import them each year, and a 4Kg box is very reasonably priced. Also, oranges for marmalade can be frozen.