An Adverse Utility Account settled in 2016 (not bankruptcy) is still on my credit report?

Docmartin2259

I had a dispute with Npower during 2015 which went to the energy ombudsman and was eventually settled in 2016. There were numerous errors by Npower and an agreement was reached. This was a period where Npower had major billing problems. 

The adverse account is listed with the 3 agency 'Check My file' (under Experian agency). Date of the dispute was logged as 2015, recorded as settled 2016. Notwithstanding the fact that the Npower complaint was upheld - I would have expected in any event that this would have dropped off my record on a time related basis. 

However Npower is recorded as closing its account in 2021 and the adverse date is recorded from the date of closure of the account in 2021. So the adverse report remains on my account today and the report says this will not be removed until March 2027. Can this be possible given the dispute took place and was settled between 2025-16? Its the only adverse report on my file and has really knocked my score down from to Fair.

To complicate matters my initial independent credit rating directly with Experien came back as Excellent - I approached a mortgage broker to look into re-mortgaging on the basis if the excellent rating in my Experien report.

I just now checked multiagency 'Check my File'  and was shocked to see this revised report rating.
I am worried this will seriously affect my re mortgage application process which I need to begin and I feel I will be perceived a misleading my mortgage Broker.

Any advice would be appreciated:
1. there is the inconsistent listing between Reports.
2. The time factor disputed account still listed from 2015-16
3. I am worried that anything I can do i.e. making a hard enquiry to Check My File to dispute and potentially correct this adverse account listing will go on the record as a correction and slow the re-mortgage process down by months and up to 1 year .