It’s not a problem. Just give us what you can. If you can’t answer a question or you don’t have the information we ask for, just tell us in the additional information section. Just because you can’t provide the information we ask for, doesn’t mean we can’t get you a refund. You should always respond to the online questions that you can, if you don’t, we probably won’t be able to finish your review, which means you’re very likely to lose any money you’re owed by HMRC.