baby clothes help!

I'm going on holiday with my (then) 5 month old little boy in January. I need to find him a cool hat to wear which will protect him from the sun but still look good. My mother-in-law has bought him a legionaries hat which is the most fugly thing I've ever seen and I neeeed to find something that he can wear instead of that...
I live in England so UK shops would be best! :)