I have these pretty regularly, usually in a stir-fry or curry, they're good! I usually soak them in v hot water for a bit, before squeezing most of the water out, then throwing in the curry/fry. Since they soak up the fluid nicely I'd imagine they work well marinated but I've not experimented much.
I love what the pitta and would like to try and make something similar at home. I think they they soya chunks like these - https://www.hollandandbarrett.com/shop/product/holland-barrett-natural-soya-protein-chunks-60082095
Does anyone have any experience of frying these and putting them in a kebab/flatbread? I've not used them at all before.