I am tired of people assuming I am a muslim because of my ethnicity

I know this will sound weird or maybe even racist to some extent but I swear I am not and I apologise if it feels that way ahead of time.
I am a Turkish-Greek who was born in UK and raised mostly in Turkey for majority of my life, as a result I have a Turkish first and last name (both are of Latin origin, so it's not a traditional muslim name). I want to mention that I am also not a muslim, and Turkey is a secular country, so I grew up with such beliefs. I have came back to UK during Sixth-Form to study, and for the longest time I can remember, whenever I would tell someone I am not a muslim, they would look at me in a shocked way, almost as if I broke their whole expectation of me. I quite literally have eaten a BLT sandwich around such people on multiple occasions too, so I don't know what's up with that.
Another thing is that, girls who I have basically never talked to or had minimal interaction with would ask me out or show romantic interest towards me. They often happened to be muslims, who would also often be shocked when I tell them I am not a muslim.
When I was having an interview for a university, despite on my UCAS form declaring that I am not a muslim, and marking my religion as agnostic, the interviewer kept talking about the turkish muslim students at the uni and assumed I was muslim too until I had to mention I am not one.
I swear I have nothing against islam or anything like that, however this has been happening for years and ONLY in the UK. I have lived in other countries and nobody assumes someone's religion because of the country they are from (despite the fact that country is obviously secular). I feel like I am just some sort of a diversity raising tool for these people. I may sound frustrated because I kind of am. Nobody assumes a Japanese person's religion but for some reason I am assumed to be a muslim by default? Can anyone tell me if they had similar experiences like this or if I am just crashing out over nothing?