Endowment Qualifying status - Changing advice from Provider

Smartpower

I took out an endowment in May 1999.  In 2013, I was considering cancelling the policy as it was performing badly, The Service Provider Friends Provident advised me that I could reduce life cover & remove critical illness (an optional part of the policy) as I already had these benefits through work.

FP sent me quotes to reduce the life cover & remove critical illness but I did not take up the offer as Aviva misadvised me on the cost of life cover & critical illness and they couldn't tell me how the change would affect several bonuses that were in the policy (e.g. loyalty bonus)

In 2016/17 FP had been taken over by Aviva but I again asked them if I could reduce cover on LA and remove CIC, they said that I could and they would send me quotes to reduce cover.  The quotes were not sent for around a year despite a number of calls and complaints. So I made a complaint to Aviva and they found in my favour paying £150 compensation and telling me that they would send me the quotes in a separate letter.  As they refused to send quotes or give me an explanation why they wouldn't I went to the Ombudsman.

Aviva told the Ombudsman that I couldn't change the policy in the last 10 years despite them sending me 5 letters and an internal complaint outcome that I could and phone calls. Aviva cited a letter they had sent to me after the start date of the complaint that said I couldn't make changes in the last 10 years of the policy.  They omitted to tell the FO that they had also sent me another 3 letters after this letter saying that I could make changes.

The Ombudsman found against me because of this letter despite it being sent after the complaint.  They stated that Aviva had said the endowment "might" become non qualifying if changes were made in the last 10 years so they couldn't do it despite the contradiction and that I hadn't taken up the offer to reduce life cover or critical illness.  The FA ignored the fact that I had 8 letters showing the provider said I could make charges in the last 10 years and the FO didn't offer compensation because they said I wouldn't have been able to make the changes anyway because Aviva said that the changes would make it non qualifying in the last 10 years. There is no specific policy in the terms and conditions that mentions "10 years" but there is 

I claim that if they hadn't told me that I could reduce the life cover and critical illness then I could have cancelled the policy and saved between  £5000 - £10000 on these premiums.  I would like to understand what makes a endowment non qualifying.

HMRC said they believed that removing optional parts of qualifying product would probably not affect the status.  The also said that changes in the last 10 years were more about stopping policyholder increasing premiums significantly in the last few years to take advantage of the qualifying status rather than reducing the cover and that I should consult with the provider to be sure.  The latest email from the provider states that I can change the policy in the final 10 years but they now won't send me the quotes because I lost the FO decision.

Does anyone know what the rules really are about qualifying status of endowments and whether I am entitled to compensation for the contradictory advice (8 letters saying I can against 1 saying I can't) that Aviva gave me for several years when I could have cancelled the policy .