recreating this sauce / recipe?

hey! it’s my first post here, hope this is ok!
i had this from m&s the other day and it was really good!! it’s actually a pretty good low cal option in itself haha but would be expensive to get this every day 😣 but when i was looking at the ingredients list online, i was wondering if i could sub some of the sauce ingredients out for an even lower cal version? that way i might be able to expand the recipe and make the portion bigger! but i’m terrible at cooking and i’m not sure how much of each ingredient exactly to add in ratio wise – would anyone have any suggestions? it doesn’t have to be exact but any ideas would be really appreciated! so far the only idea i have is to use greek yoghurt instead of cream but thats about it… thanks in advance!!