I did just write TU a letter about some accounts just like you have (showing lates, etc.) and within 3 weeks they had cleaned up my report and even cleaned up some stuff I didn't inquire about! I have to write them another though about 2 inquiries on my report which I failed to include.
Start by sending a letter to them about the accounts you are questionning. I did mine less than a month ago and got my response and new credit report last week! I was very pleased with the outcome.