Npower, Experian and the Ombudsman

Hi,
After some advice - Npower hammered my Experian credit file last year and as a result, I took them to the Ombudsman.
The issue was around a final bill, which was sent to a 3rd party without my knowledge and luckily, I checked my file and saw it
Not wishing to go into detail with that, but fully paid it in Sept 2016, even though the 3rd party took full payment and passed it to Npower a month later - Npower would not accept payment otherwise !
Anyway, we move on - The Ombudsman found partially in my favour and asked Npower to do the following :


Following my investigation of your complaint, my decision requires npower (residential) to:



· liaise with the third party debt collection agents to confirm the date you made the final payment to clear the balance;
· provide confirmation in writing that no adverse credit information has been recorded after the final payment was made;
· If it has recorded adverse credit information after this date it should provide confirmation in writing that it will correct the credit information shared; and
· provide you with an apology in writing for the inconvenience experienced.


From the above, my expectation was that Npower, would adjust the credit file to show the balance paid from Sept 2016 . They wrote and said they would do the above
My credit file, which I recently bought, now has a U placed against the debt, the late payments still show up to and include Sept and October , even though they claim they have carried out the Ombudsman's request
I have queried with Experian, when my file was last updated and they have not provided an answer other than the below- I have emailed 5 times to ask
The information we hold actually belongs to lenders. Only they can amend it or tell us to amend it for them.
The Ombudsman have stated that Npower have told them they have carried it out and I now have to send a pic of the recent credit file entry as they don't understand credit files


My queries are as follows:
1) As the Experian updates would relate to last Sept and Oct, is it worth pursuing ? My file has no missed payments for well over 2 years , other than Npower - this is now 5 months ago
2) What effect will a U have on my file ? I am hoping to take some money out of the large amount of equity I have in my home for improvements and am unsure whether this will affect the application
This is worrying me as I am semi retired, have very little debt, a good income and don't want to harm my credit files with a turned down application
Many thanks all