Five At The Bridge, KT8 9EU
It's an unassuming presence to be sure, and there are plenty of other cafes along this stretch of road by Hampton Court Bridge which look far more tricked up, but the food is good solid fare at a good value. Service is laidback and tables are set out in a plain room, with simple tablecloths.
A range of basic sandwiches is on offer, with sparse options for vegetarians (brie, cheddar, or egg mayo basically), as well as some daily specials (pasta-based on my visit, at a more substantial price of around £8).
They have a large range of cakes displayed in the window (over 15), all of which look very tasty, as indeed the coffee & walnut cake was.