Never send an example of your tax return to the Revenue
A recent First Tier Tribunal case highlights the dangers of writing to HMRC.
The taxpayer was intending to submit an electronic tax return before the 31st January.
Unsure that they had done it right, the taxpayer printed their intended submission and sent it to HMRC for them to cast their eye over and give pre-submission feedback.
HMRC did what they always do. They tore off and discarded the covering letter, explaining the reason they had got a paper tax return and processed it as the final submission.
Being after 31st October, a late-filing penalty was issued.
As counter-intuitive as it might seem, every accountant in the land would have predicted this outcome, so never send an example of your tax return in to HMRC for pre-approval. It will always get treated as the final return, because HMRC never read covering letters.