Documentation needed for 6 day trip?

So I admit - I'm a worry wort, and for that I apologize.  I've never brought any bank statements/proof of employment before when I've traveled to the UK, but now that it is becoming more frequent (I was there in October and am going back next week), would it be advisable to bring one or both of these "just in case"?  If so, which is more important/valuable? Of course, I will have my itinerary with me to show I am not even staying a full week. 

Thanks.

Documents

I wouldn't imagine staying less than a week would raise any eyebrows. An itinerary and/or letter from your employer "should" be enough...but 6 days isn't much to bat an eyelash at.

Perfect. Thank you.  I'll get a letter just for kicks