Hi Gynefor,
With you top off you look like you have just got a well built chest and are in good shape.. with your white t shirt I can see how it it annoys you, but very few people look good in a white tshirt!
It's a tough call - maybe stick to dark coloured tops like black tshirts etc because with your top off you just look like a guy that does weights and is in good shape.
Take care