I use a letter that is not formal, and has the impression of fun, font I use also has a modern look,
because you want a logo that is simple and not too many pictures, then I combine the letters U and B into an image beers with foam above it, so that this image represents your pub is clean, tidy and pleasant
for color, I try to use the purple color of some favourit color of your choice.
Let me know if this is heading in the right direction and if there is anything you would like me to tweak in the logo, i.e. fonts, colors, images etc.