While the incomplete records may be because you haven't filed taxes for two years ago, with regard to the capacity to revise and refile your taxes, especially when it comes to independent income earners, there are expenses that sometimes can be carried over year to year that may allow you to qualify. One piece of advice that is in the letter but that should also be distributed by MPs is to take a look at those options in terms of some of the flexibility that gig economy or self-employed workers enjoy.
In other words, if you file now, you can always revise it later if new information becomes available or new tax law is applicable.