Filing amended FBAR for UK-based pension accounts

I have been reporting all my UK bank, NS&I and savings accounts on my annual FBAR to this point. From what I've been reading here I believe I should also have been listing my UK pension accounts too (even though I have not started drawing any funds from them).

Assuming I do need to report pension accounts, how should I fix this error? Should I just file a single amended FBAR for my most recent year and continue declaring them in future years? Or is there another better way to do this? Do I need to go back 6 years to file amended FBARs for the previous erroneous years too?

As always, thank you for your thoughts and suggestions.

Maybe best to do the 6 years, as I believe this is the statue of limitation period. As I did not take a distribution, so checked the maximum value unknown box. If you purchase an annuity or drawdown you can then enter that figure going forward. You probably know that the pension needs to be filed on 8938 if you meet thresholds.